Justice O’Connor
delivered the opinion of the Court.
This case presents the question whether a state university’s delivery of unstamped letters from a labor union to university employees violates the Private Express Statutes, 18 U. S. C. §§ 1693-1699, 39 U. S. C. §§ 601-606. These statutes establish the postal monopoly and generally prohibit the private carriage of letters over postal routes without the payment of postage to the United States Postal Service.
I
Appellant Regents govern a large state-owned university with over 100,000 employees. The university (hereafter referred to as appellant) operates an internal mail system to facilitate the delivery of mail to the various sites on its campuses. Appellant’s employees collect mail originating on the campuses from many mail depositories and take it to a central location for sorting. The mail is separated into three groups: (1) mail already bearing United States postage; (2) unstamped internal university mail; and (3) other unstamped mail. Group (1) is delivered to the Postal Service without further handling by appellant. Group (2) is monitored to ensure that it includes only official university mail. Group (3) is examined for any letters addressed to university destinations that come within an exception to the Private Express Statutes and can therefore be delivered by the appellant without postage. Appellant affixes United States postage to the remainder of mail in group (3) and delivers it to the Postal Service, then charges the senders for the costs involved.
In late 1979, appellee William H. Wilson, president of appellee Local 371 of the American Federation of State, County, and Municipal Employees (Union), attempted to use appellant’s internal mail system to send unstamped letters from the Union to certain employees of appellant. The Union represented these employees and had filed a request for recognition of a bargaining unit. A subsequent unit determination, however, placed these employees in a different bargaining unit. Brief for Appellee Wilson 2, n. 2. Appellant refused to carry the letters in its internal mail system on the ground that the Private Express Statutes prohibited such carriage. Believing that this refusal violated a state law, the Higher Education Employer-Employee Relations Act (HEERA), Cal. Govt. Code Ann. §§3560-3599 (West 1980), Wilson and the Union filed an unfair labor practice charge with appellee California Public Employment Relations Board (PERB), the state agency charged with interpretation and enforcement of HEERA.
Before PERB, appellant argued that the carriage of the Union letters would violate the Private Express Statutes; it relied on an advisory opinion from the United States Postal Service to that effect. Advisory Op., PES No. 82-9 (July 2, 1982), App. to Juris. Statement A66. Wilson and the Union in turn argued that refusal to carry the letters violated HEERA’s requirement that employers grant unions access to their “means of communication.” PERB initially declined to consider the federal law issues pressed by appellant and held that HEERA required delivery of the letters. The California Court of Appeal agreed with PERB’s determination that denial of access violated HEERA, but noted that the HEERA right of access was expressly subject to “reasonable regulations.” 139 Cal. App. 3d 1037, 1041, 189 Cal. Rptr. 298, 300-301 (1983). The court found an unresolved factual issue, namely, whether appellant’s denial of access was a “reasonable regulation” in light of all the surrounding circumstances, including the Private Express Statutes. It therefore remanded the case back to PERB for consideration of this issue. Id., at 1042, 189 Cal. Rptr., at 301. On remand, PERB found this HEERA requirement to be consistent with federal law because it determined that the carriage involved was within two different exceptions to the Private Express Statutes, namely the “letters-of-the-carrier” exception, 18 U. S. C. § 1694; 39 CFR § 310.3(b) (1987), and the “private-hands” exception, 18 U. S. C. § 1696(c); 39 CFR § 310.3(c) (1987).
The California Court of Appeal affirmed. 182 Cal. App. 3d 71, 227 Cal. Rptr. 57 (1986). The court concluded that the “letters-of-the-carrier” exception permitted the delivery of the Union’s letters through appellant’s internal mail system. In light of this conclusion, the court declined to address the “private-hands” exception. Id., at 77, 227 Cal. Rptr., at 60. The California Supreme Court denied appellant’s petition for review. App. to Juris. Statement A-13. We noted probable jurisdiction, 483 U. S. 1004 (1987), and now reverse.
II
Congress enacted the Private Express Statutes pursuant to its constitutional authority to establish “Post Offices and post roads,” U. S. Const., Art. I, § 8, cl. 7. In general these statutes establish the United States Postal Service as a monopoly by prohibiting others from carrying letters over postal routes.
A postal monopoly has prevailed in this country since the Articles of Confederation, see Act of Oct. 18, 1782, 23 J. Continental Cong. 672-673 (G. Hunt ed. 1914), and Congress embraced the concept in its first postal law, see Act of Feb. 20, 1792, ch. 7, § 14, 1 Stat. 236. Because Congress desires “prompt, reliable, and efficient services to [postal] patrons in all areas,” 39 U. S. C. § 101(a) (emphasis added), it has enacted the Private Express Statutes and has provided for nationwide delivery of mail at uniform rates.
There is no doubt that the general prohibition would apply to the carriage involved here, see 18 U. S. C. §§ 1693, 1694, so the central issue is whether such carriage is within one of the numerous exceptions to the Private Express Statutes. Appellees urge that both the “letters-of-the-carrier” and “private-hands” exceptions apply. We consider each in turn.
A
The letters-of-the-carrier exception is founded on the portion of 18 U. S. C. § 1694 italicized below:
“Whoever . . . carries, otherwise than in the mail, any letters or packets, except such as relate . . .'to the current business of the carrier . . . shall, except as otherwise provided by law, be fined not more than $50.” (Emphasis added.)
It is this exception that allows appellant to operate an internal mail system at all. To fall within the exception, the face of the statute requires that the letters “relate” to the “current business” of the carrier. Precisely what constitutes a carrier’s “current business” is not further described. The ordinary sweep of the term, however, falls far short of encompassing the letters involved in this case. The letters relate to the Union’s efforts to organize certain of appellant’s employees into a bargaining unit. This is a subject in which appellant certainly is interested, but it is also a subject which can be accurately described only as the Union’s current business, not appellant’s. It strains the statutory language to contend that the phrase “current business” includes such activity.
Appellees argue that California has through HEERA made harmonious labor relations the business of its state universities, and thus in a sense the Union’s business is the university’s business. Cf. Cal. Govt. Code Ann. § 3560(a) (West 1980) (“fundamental interest in the development of harmonious and cooperative labor relations”). To be sure, a State generally is free to define the nature of its institutions and the scope of their activities as it sees fit. But this principle must have some limits in this context for, otherwise, a State could define delivery of mail to all its citizens as the “current business” of some state agency and thereby defeat the postal monopoly. Appellees are urging far too expansive a reading of the statute. We rely on the normal meaning of the language chosen by Congress and conclude that the letters-of-the-carrier exception does not permit appellant to carry the Union’s letters.
The legislative history confirms our reading of the statutory language, making clear that the exception is a narrow one. Congress added the letters-of-the-carrier exception to the Private Express Statutes in 1909. Until that time, the prohibition on private carriage was unqualified. The new exception responded to an Opinion of the Attorney General rendered in 1896. 21 Op. Atty. Gen. 394, 397-399. That opinion concerned a Postal Department regulation that allowed railroads to carry their own mail. The Attorney General said that the regulation was valid because two conditions were present. First, the letters were related to the carrier’s business. Second, the letters were “letters sent by or addressed to the carrying company, or on its behalf.” Id., at 400. The Attorney General concluded that without the second condition, the implied exception would be too broad.
Congress generally approved of the Attorney General’s decision, but some Members found the exception difficult to square with the express, unqualified language of the statute. See 42 Cong. Rec. 1901-1905 (1908). Therefore a movement began to amend the statute to include the present exception for letters that relate to “the current business of the carrier.” Id., at 1976. See Act of Mar. 4, 1909, ch. 321, § 184, 35 Stat. 1124. Senator Sutherland, the sponsor of the specific amendment, explained its intent:
“I move that amendment because I think that it puts in express language precisely what the section means as it stands without it ... . I think the opinion of the Attorney-General . . . gives the correct construction to this section. The section is dealing with the carrying of mail for others. It is not dealing with the question of the carrying of the mail for the carrier itself.” 42 Cong. Rec. 1976 (1908).
The House Report reflected a similar intent that the amendment put the statute “in exact conformity with the construction placed upon existing law.” 43 Cong. Rec. 3790 (1909) (referring to 21 Op. Atty. Gen. 394 (1896)).
This history suggests an intention to codify the Attorney General’s construction. That construction includes a requirement that the letters be “sent by or addressed to the carrying company, or on its behalf,” to qualify for the letters-of-the-carrier exception. 21 Op. Atty. Gen., at 400. See also 29 Op. Atty. Gen. 418, 419 (1912) (“Congress has imposed two conditions upon the free transportation of letters outside the mail: First, that the letters should be the letters of the carrier itself; and second, that they should relate to its own current business”); 28 Op. Atty. Gen. 537 (1910).
Our only previous decision concerning the letters-of-the-carrier exception, United States v. Erie R. Co., 235 U. S. 513 (1915), is consistent with a narrow view of the statutory language. Erie involved carriage by a railroad of letters concerning a joint venture between the railroad and a telegraph company. The Court simply held that the “business of the carrier” included the business of the joint enterprise. Erie therefore sheds no light on the proper construction of the statute in this quite different context. Moreover, the specific letters involved in Erie fall within our view of the proper scope of the statute. They were written by an employee of the railroad in his official capacity and addressed to other employees in their capacities as representatives of the railroad.
Particularly in light of the clarifying legislative history, we conclude that the letters-of-the-carrier exception is far narrower than appellees would have it. Cf. Tanner v. United States, 483 U. S. 107, 125 (1987); Dixson v. United States, 465 U. S. 482, 491-496 (1984). Whether or not it can be read to include a requirement that the letters be written by or addressed to the carrier, a question we need not reach, it is at least limited to “business of the carrier” that is closer to the carrier’s own affairs than the letters involved here. The alleged “business” in this case is not close enough to appellant’s affairs to be the natural subject of letters concerning appellant’s “current business.” Accordingly, we hold that the letters-of-the-carrier exception does not permit appellant to carry the Union’s letters.
B
The private-hands exception derives from 18 U. S. C. § 1696(c):
“This chapter shall not prohibit the conveyance or transmission of letters or packets by private hands without compensation.”
From its inception, the monopoly granted the Postal Service had always been limited to the carriage of mail “for hire.” See Act of Oct. 18, 1782, 23 J. Continental Cong. 670, 672-673 (G. Hunt ed. 1914); Act of Feb. 20, 1792, ch. 7, § 14, 1 Stat. 236. The private-hands exception is a reflection of the limited nature of the monopoly; it was designed to ensure that private carriage is not undertaken “for hire or reward.” Ibid. While the limited nature of the postal monopoly always implied that private, gratuitous carriage was excepted from the prohibitions of the Private Express Statutes, Congress made the exception express in 1845, at a time when it was greatly concerned with the dwindling revenues of the Postal Service. See S. Rep. No. 137, 28th Cong., 1st Sess., 1, 10 (1844); H. R. Rep. No. 477, 28th Cong., 1st Sess., 1 (1844). To increase postal revenues, Congress lowered prices and limited franking privileges. Congress also sought to boost revenues by eliminating competition. Therefore, it strengthened the general prohibition on private carriage, intending to “put an end to all interference with the revenues of the department” from that source. S. Rep. No. 137, supra, at 10. Against this backdrop, Congress developed a narrow exception for carriage by “private hands,” crafting the exception in such a way as to permit only gratuitous carriage undertaken out of friendship, not pursuant to a business relationship. H. R. Rep. No. 477, supra, at 4 (“Penalties are provided . . . with exceptions in favor of the party . . . who conveys the letter out of neighborly kindness, without fee or reward”).
Congress used unambiguous language to accomplish its goals. Persons or entities other than the United States Postal Service — i. e., “private hands” — may carry letters without violating the Private Express Statutes only so long as they do not receive any form of benefit from the sender— i. e., “without compensation.” While the pivotal term, “compensation,” is not further defined, Congress in no way qualified its reach. We therefore give effect to congressional intent by giving the language its normal meaning. A dictionary from the period during which the private-hands exception was enacted illustrates the general nature of the term; it defines compensation to include “that which supplies the place of something else” and “that which is given or received as an equivalent for services, debt, want, loss, or suffering.” N. Webster, An American Dictionary of the English Language 235 (C. Goodrich ed. 1849). Accordingly, we hold that the private-hands exception is available only when there is no compensation of any kind flowing from the sender to the carrier.
A business relationship between the two parties may render the exception unavailable, because acts undertaken in the course of such a relationship may involve an exchange of benefits or a quid pro quo. Congress understood this point. Early in the debates on the 1909 amendments to the Private Express Statutes, which added the letters-of-the-carrier exception, Senator Sutherland expressed concern that adding such an exception would permit railroads to agree to carry mail for each other. He was concerned that by undertaking such carriage pursuant to “some common understanding,” the railroads “would not be carrying for compensation.” Senator McLaurin, one of the supporters of amendment, responded: “[A]n arrangement of that kind . . . would itself be for compensation. It would be a quid pro quo and it would violate the law.” Senator Sutherland evidently accepted this view for, as noted above, he sponsored the actual amendment that became the letters-of-the-carrier exception. The construction Congress placed on the private-hands exception is perhaps best summarized through Senator McLaurin’s statement that an exception for carriage without compensation was intended solely to permit “an innocent man ... to do a favor to some[one].” 42 Cong. Rec. 1905 (1908). A business relationship ordinarily converts such “favors” at the very least into implicit attempts to further the business relationship.
The private-hands exception consistently has been interpreted as not authorizing carriage pursuant to a business relationship. Thus, “compensation” has been read to encompass the nonmonetary consideration that is implicit in a business relationship. United States v. Thompson, 28 F. Cas. 97 (No. 16,489) (DC Mass. 1846). Thompson involved the prosecution of the proprietor of a delivery service for carrying letters along with other merchandise. The defendant argued that he carried letters only in connection with delivery of other merchandise and that he received no additional compensation for carrying the letters with the merchandise. In essence, the defendant contended that he carried the letters only as a gesture of good will. The court rejected this argument, holding that the statute did not permit the carriage of letters “as a part of his business of a merchandise express, although no charge was made for letters as such. ” Id., at 98.
The Attorney General took a similar view of the exception’s scope when he opined that railroads could not agree to carry each other’s mail, because the “express or implied obligation of railroads to carry letters for each other . . . would amount to ‘compensation’ within the meaning of the statute.” 21 Op. Atty. Gen., at 401.
Applying this well-established construction to the situation at hand, we conclude that appellant’s carriage of the Union’s letters would not be “without compensation.” Appellees initially argue that there would be no compensation because the Union would not pay appellant specifically to carry the letters. This obviously gives far too restrictive a reading to the term “compensation.” That term includes indirect as well as direct compensation. If we read the exception to include any private carriage so long as no direct payment is made, it quickly would swallow the rule; senders and carriers could manipulate their relationships to avoid direct compensation and thereby evade the Private Express Statutes.
Appellees also argue that compensation would be lacking because appellant merely would perform a mandatory duty imposed by state law. This lack of legal consideration, appellees argue, demonstrates that the carriage is not part of any business relationship. As a matter of general contract law, it may be true that performance of a legal duty cannot constitute legal consideration. Common-law notions of consideration, however, do not control the interpretation of this statute. Congress, after all, used the generic term “compensation,” which can include less direct exchanges of benefits.
Here there is an arm’s-length business relationship between the Union and the employees on the one side and appellant on the other. By delivering the Union’s letters, appellant would perform a service for its employees that they would otherwise pay for themselves, through their union dues. This service would become part of the package of monetary and nonmonetary benefits that appellant provides to its employees in exchange for their services. In our view, carriage of the Union’s letters pursuant to such an exchange of benefits necessarily means that the carriage is not “without compensation.” Accordingly, it does not fall within the private-hands exception.
C
The parties and the United States as amicus curiae have focused their arguments largely on Postal Service regulations construing the letters-of-the-carrier and the private-hands exceptions. With respect to the letters-of-the-carrier exception, the Postal Service has consistently read the'statute to require that the letters be written by or addressed to the carrier. Even before the Service issued formal regulations, it espoused this view in periodic pamphlets it published describing the reach of the Private Express Statutes. See, e. g., United States Post Office Dept., Restrictions on Transportation of Letters 16-17 (4th ed. 1952). When it issued formal regulations, the Postal Service included the requirement that the letters be the carrier’s own:
“The sending or carrying of letters is permissible if they are sent by or addressed to the person carrying them. If the individual actually carrying the letters is not the person sending the letters or to whom the letters are addressed, then such individual must be an officer or employee of such person (see [39 CFR] § 310.3(b)(2)) and the letters must relate to the current business of such person.” 39 CFR § 310.3(b) (1987).
The Postal Service’s regulations also read “compensation” for purposes of the private-hands exception in a way consistent with our evaluation of the term. They describe the exception’s scope as follows:
“The sending or carrying of letters without compensation is permitted. Compensation generally consists of a monetary payment for services rendered. Compensation may also consist, however, of non-monetary valuable consideration and of good will. Thus, for example, when a business relationship exists or is sought between the carrier and its user, carriage by the carrier of the user’s letter will ordinarily not fall under this exception.” § 310.3(c).
Appellant and the United States have urged us to defer to these agency constructions of the statute. While they reach a different conclusion as to the proper application, appellees specifically indicated at oral argument that they were not challenging the validity of the regulations. Tr. of Oral Arg. 33. Because we have been able to ascertain Congress’ clear intent based on our analysis of the statutes and their legislative history, we need not address the issue of deference to the agency.
Ill
The California Court of Appeal incorrectly concluded that the carriage of letters involved in this case was within an exception to the Private Express Statutes. Properly construed, neither of the statutory exceptions proffered by appellees —the letters-of-the-carrier exception and the private-hands exception — permits appellant to carry the Union’s letters in its internal mail system. Accordingly, the judgment of the California Court of Appeal is
Reversed.
Justice Kennedy took no part in the consideration or decision of this case. -
The Postal Service is authorized to suspend the operation of the Private Express Statutes when required by the “public interest,” 39 U. S. C. § 601(b). In this case, PERB also found that the Postal Service’s “suspension” for letters of “bona fide student or faculty organizations,” 39 CFR § 320.4 (1987), applied to the letters involved here and therefore permitted their carriage by appellant. The California Court of Appeal did not address this ground and PERB has expressly declined to press it before this Court. Brief for Appellee PERB 16, n. 9. Accordingly, we do not consider the applicability of the suspension.
Contrary to the suggestion in the dissent, post, at 611-612, n. 5, this qualified statement obviously does not purport to render the private-hands exception automatically inapplicable whenever a business relationship exists. Rather, it simply indicates that a business relationship ordinarily suggests that the carriage is not without compensation. Cf. 39 CFR § 310.3(e) (1987).