opinion: Per Curiam.
  Appellee American Friends Service Committee (employer) is a religious corporation, whose principal operation is philanthropic work and many of whose employees are conscientious objectors to war, performing alternative civilian service. Appellees Lorraine Cleveland and Leonard Cadwallader (employees) are present or past employees of the employer.
  Because of their religious beliefs, the employees in 1969 requested their employer to cease withholding 51.6% of the portion of their wages required to be withheld under § 3402 of the Internal Revenue Code. Although they conceded that these amounts were legally due to the Government, they wished to bear witness to their beliefs by reporting the amounts as taxes owed on their annual income tax returns but refusing to pay such amounts. They would thus compel the Government to levy in order to collect the taxes.
  In response to the employees’ request, the employer ceased withholding from the employees’ salaries 51.6% of that amount required to be withheld under § 3402, although it continued to pay the full amount required to be withheld under that provision to the Government. It then brought a suit for refund of the amount it had paid to the Government but not actually withheld from salaries. The appellee employees joined the employer’s action, seeking on their own behalf an injunction barring the United States’ enforcement of § 3402 against the employer with regard to 51.6% of the required withholding. They argued that, even though they were liable for these amounts, § 3402 as applied to this portion of their wages was unconstitutional as a deprivation of their right to free exercise of religion under the First Amendment since it did not allow them to bear witness to their beliefs by refusing to voluntarily pay a portion of their taxes.
  The District Court ordered a refund of amounts tendered by the employer but not withheld by it, since the Government had also levied on the employees for these taxes and hence had received a double payment of the amount due. The Government does not contest this portion of the District Court’s judgment.
  The District Court also enjoined the United States from enforcing § 3402 against the employer with respect to 51.6% of the required withholding from the employees’ salaries, holding that § 3402 as applied to this amount constituted an unconstitutional abridgment of the right to free exercise of religion. The United States appeals this portion of the judgment. The District Court’s opinion and order were entered before this Court handed down its opinions in Bob Jones University v. Simon, 416 U. S. 725 (1974), and Commissioner v. “Americans United” Inc., 416 U.S. 752 (1974).
  The Anti-Injunction Act, 26 U. S. C. § 7421 (a), provides that no suit for the purpose of restraining the assessment or collection of any tax shall be maintained in any court by any person, whether or not such person is the person against whom such tax was assessed.” In Bob Jones, supra, we rejected an appeal to create judicial exceptions to § 7421 (a) other than that carved out in Enochs v. Williams Packing & Navigation Co., Inc., 370 U. S. 1 (1962). We noted that Williams Packing was the “capstone” of judicial construction of the Act and spelled an end to cyclical departures from the Act’s plain meaning. Bob Jones University v. Simon, supra, at 742. In “Americans United” Inc., supra, we stated that a pre-enforcement injunction against the assessment or collection of taxes could be granted only if it were clear that the Government could in no circumstances ultimately prevail on the merits, and that equity jurisdiction existed. “Unless both conditions are met, a suit for preventive injunctive relief must be dismissed.” 416 U. S., at 758.
  The employees concede, and the District Court found, that § 3402 withholding is a method of collection of taxes within the meaning of § 7421 (a). They further concede, as they must, that they are not within the Williams Packing exception; far from the Government’s defense in a refund suit being meritless, the employees concede that the Government would undoubtedly prevail in such a refund action.
  They contend, however, that since the District Court enjoined only one method of collection, and the Government is still free to assess and levy their taxes when due, the Act does not apply. But this contention ignores the plain wording of the Act which proscribes any “suit for the purpose of restraining the assessment or collection of any tax.” The District Court’s injunction against the collection of the tax by withholding enjoins the collection of the tax, and is therefore contrary to the express language of the Anti-Injunction Act.
  The employees also argue that the Anti-Injunction Act is inapplicable because they have no alternative legal remedy available. They contend that a refund suit would be an inadequate remedy, in view of the concession on their part that the taxes are due, since they would surely lose such an action. But this ignores the fact that inadequacy of available remedies goes only to the existence of irreparable injury, an essential prerequisite for traditional equity jurisdiction, but only one of the two parts of the Williams Packing test. Commissioner v. “Americans United” Inc., supra, at 762; Bob Jones University v. Simon, supra, at 745. Here as in “Americans United” Inc., supra, the employees will have a “full opportunity to litigate” their tax liability in a refund suit. 416 U. S., at 762. Even though the remitting of the employees to a refund action may frustrate their chosen method of bearing witness to their religious convictions, a chosen method which they insist is constitutionally protected, the bar of the Anti-Injunction Act is not removed:
  “[Decisions of this Court make it unmistakably clear that the constitutional nature of a taxpayer’s claim, as distinct from its probability of success, is of no consequence under the Anti-Injunction Act.” Id., at 759.
  See also Lockerty v. Phillips, 319 U. S. 182, 187 (1943).
  In Bob Jones we left open the question of whether in-junctive relief as to future collection would be proper as a form of ancillary relief in a refund suit where the taxpayer prevailed on the merits, in order to avoid the necessity of continuous subsequent “backward-looking refund suits.” 416 U. S., at 748 n. 22. That situation is not presented here since the employees have never brought a refund action, much less prevailed on the merits of such an action. Their joinder in the employer’s successful refund action, based on the receipt of double payment by the Government, would afford no basis for injunctive relief based on their constitutional claim. The injunctive relief granted by the District Court in this case is plainly at odds with the dual objectives of the Act: efficient and expeditious collection of taxes with “a minimum of pre-enforcement judicial interference,” and protection of the collector from litigation pending a refund suit. Bob Jones, supra, at 736-737
  The judgment of the District Court is reversed insofar as it enjoins the collection of taxes by the Government and the withholding of wages by the employer.
  Reversed in part.
  This figure represents their estimate of the percentage of the federal budget which is military related.
  26 U. S. C. § 3402. The provision provides in part that “[e'Jvery employer making payment of wages shall deduct and withhold upon such wages (except as otherwise provided in this section) a tax determined in accordance with the following tables. . . .” There is no dispute as to the applicability of the provision to the employees’ wages.
  Jurisdictional Statement 7 n. 3. We express no opinion as to the merits of the refund claim. The lower court’s opinion is reported at 368 F. Supp. 1176.
  Since the District Court held that § 3402 was unconstitutional as applied to the facts of this ease, this Court has jurisdiction over the appeal under 28 U. S. C. § 1252. Fleming v. Rhodes, 331 U. S. 100, 102-103 (1947); United States v. Christian Echoes Ministry, 404 U. S. 561, 563 (1972).
  See Act of Mar. 2, 1867, § 10, 14 Stat. 475; Rev. Stat. §3224; Int. Rev. Code of 1939 § 3653. Section 7421 (a) of the Code states: “Except as provided in sections 6212 (a) and (c), 6213 (a), and 7426 (a) and (b)(1), no suit for the purpose of restraining the assessment or collection of any tax shall be maintained in any court by any person, whether or not such person is the person against whom such tax was assessed.”
  The legislative history of this provision enacted in 1943 indicates that its purpose in part was to assist the Government in securing needed revenue without having to resort to levy. H. R. Rep. No. 268, 78th Cong., 1st Sess., 1-2 (1943); S. Rep. No. 221, 78th Cong., 1st Sess., 1 (1943). The District Court noted that relegating the Government to levying after returns were filed would be an inefficient process. 368 F. Supp., at 1180.
  Because we have concluded that the Anti-Injunction Act bars injunctive relief, we have not found it necessary to decide other threshold issues such as whether a three-judge District Court was required, whether the sovereign immunity of the United States barred the suit, and whether the requirements of 28 U. S. C. § 1331 were met.
choices: attorney general of the United States, or his office specified state board or department of education city, town, township, village, or borough government or governmental unit state commission, board, committee, or authority county government or county governmental unit, except school district court or judicial district state department or agency governmental employee or job applicant female governmental employee or job applicant minority governmental employee or job applicant minority female governmental employee or job applicant not listed among agencies in the first Administrative Action variable retired or former governmental employee U.S. House of Representatives interstate compact judge state legislature, house, or committee local governmental unit other than a county, city, town, township, village, or borough governmental official, or an official of an agency established under an interstate compact state or U.S. supreme court local school district or board of education U.S. Senate U.S. senator foreign nation or instrumentality state or local governmental taxpayer, or executor of the estate of state college or university United States State person accused, indicted, or suspected of crime advertising business or agency agent, fiduciary, trustee, or executor airplane manufacturer, or manufacturer of parts of airplanes airline distributor, importer, or exporter of alcoholic beverages alien, person subject to a denaturalization proceeding, or one whose citizenship is revoked American Medical Association National Railroad Passenger Corp. amusement establishment, or recreational facility arrested person, or pretrial detainee attorney, or person acting as such;includes bar applicant or law student, or law firm or bar association author, copyright holder bank, savings and loan, credit union, investment company bankrupt person or business, or business in reorganization establishment serving liquor by the glass, or package liquor store water transportation, stevedore bookstore, newsstand, printer, bindery, purveyor or distributor of books or magazines brewery, distillery broker, stock exchange, investment or securities firm construction industry bus or motorized passenger transportation vehicle business, corporation buyer, purchaser cable TV car dealer person convicted of crime tangible property, other than real estate, including contraband chemical company child, children, including adopted or illegitimate religious organization, institution, or person private club or facility coal company or coal mine operator computer business or manufacturer, hardware or software consumer, consumer organization creditor, including institution appearing as such; e.g., a finance company person allegedly criminally insane or mentally incompetent to stand trial defendant debtor real estate developer disabled person or disability benefit claimant distributor person subject to selective service, including conscientious objector drug manufacturer druggist, pharmacist, pharmacy employee, or job applicant, including beneficiaries of employer-employee trust agreement, employee health and welfare fund, or multi-employer pension plan electric equipment manufacturer electric or hydroelectric power utility, power cooperative, or gas and electric company eleemosynary institution or person environmental organization employer. If employer's relations with employees are governed by the nature of the employer's business (e.g., railroad, boat), rather than labor law generally, the more specific designation is used in place of Employer. farmer, farm worker, or farm organization father female employee or job applicant female movie, play, pictorial representation, theatrical production, actor, or exhibitor or distributor of fisherman or fishing company food, meat packing, or processing company, stockyard foreign (non-American) nongovernmental entity franchiser franchisee lesbian, gay, bisexual, transexual person or organization person who guarantees another's obligations handicapped individual, or organization of devoted to health organization or person, nursing home, medical clinic or laboratory, chiropractor heir, or beneficiary, or person so claiming to be hospital, medical center husband, or ex-husband involuntarily committed mental patient Indian, including Indian tribe or nation insurance company, or surety inventor, patent assigner, trademark owner or holder investor injured person or legal entity, nonphysically and non-employment related juvenile government contractor holder of a license or permit, or applicant therefor magazine male medical or Medicaid claimant medical supply or manufacturing co. racial or ethnic minority employee or job applicant minority female employee or job applicant manufacturer management, executive officer, or director, of business entity military personnel, or dependent of, including reservist mining company or miner, excluding coal, oil, or pipeline company mother auto manufacturer newspaper, newsletter, journal of opinion, news service radio and television network, except cable tv nonprofit organization or business nonresident nuclear power plant or facility owner, landlord, or claimant to ownership, fee interest, or possession of land as well as chattels shareholders to whom a tender offer is made tender offer oil company, or natural gas producer elderly person, or organization dedicated to the elderly out of state noncriminal defendant political action committee parent or parents parking lot or service patient of a health professional telephone, telecommunications, or telegraph company physician, MD or DO, dentist, or medical society public interest organization physically injured person, including wrongful death, who is not an employee pipe line company package, luggage, container political candidate, activist, committee, party, party member, organization, or elected official indigent, needy, welfare recipient indigent defendant private person prisoner, inmate of penal institution professional organization, business, or person probationer, or parolee protester, demonstrator, picketer or pamphleteer (non-employment related), or non-indigent loiterer public utility publisher, publishing company radio station racial or ethnic minority person or organization protesting racial or ethnic segregation or discrimination racial or ethnic minority student or applicant for admission to an educational institution realtor journalist, columnist, member of the news media resident restaurant, food vendor retarded person, or mental incompetent retired or former employee railroad private school, college, or university seller or vendor shipper, including importer and exporter shopping center, mall spouse, or former spouse stockholder, shareholder, or bondholder retail business or outlet student, or applicant for admission to an educational institution taxpayer or executor of taxpayer's estate, federal only tenant or lessee theater, studio forest products, lumber, or logging company person traveling or wishing to travel abroad, or overseas travel agent trucking company, or motor carrier television station union member unemployed person or unemployment compensation applicant or claimant union, labor organization, or official of veteran voter, prospective voter, elector, or a nonelective official seeking reapportionment or redistricting of legislative districts (POL) wholesale trade wife, or ex-wife witness, or person under subpoena network slave slave-owner bank of the united states timber company u.s. job applicants or employees Army and Air Force Exchange Service Atomic Energy Commission Secretary or administrative unit or personnel of the U.S. Air Force Department or Secretary of Agriculture Alien Property Custodian Secretary or administrative unit or personnel of the U.S. Army Board of Immigration Appeals Bureau of Indian Affairs Bonneville Power Administration Benefits Review Board Civil Aeronautics Board Bureau of the Census Central Intelligence Agency Commodity Futures Trading Commission Department or Secretary of Commerce Comptroller of Currency Consumer Product Safety Commission Civil Rights Commission Civil Service Commission, U.S. Customs Service or Commissioner of Customs Defense Base Closure and REalignment Commission Drug Enforcement Agency Department or Secretary of Defense (and 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Activities Control Board Small Business Administration Securities and Exchange Commission Social Security Administration or Commissioner Selective Service System Department or Secretary of the Treasury Tennessee Valley Authority United States Forest Service United States Parole Commission Postal Service and Post Office, or Postmaster General, or Postmaster United States Sentencing Commission Veterans' Administration War Production Board Wage Stabilization Board General Land Office of Commissioners Transportation Security Administration Surface Transportation Board U.S. Shipping Board Emergency Fleet Corp. Reconstruction Finance Corp. Department or Secretary of Homeland Security Unidentifiable International Entity