Mr. Justice Douglas
delivered the opinion of the Court.
Respondent is a union that had a collective-bargaining agreement with an employer which contained a maintenance-of-membership clause providing that members were, as a condition of employment, to remain in good standing “as to payment of dues” for the duration of the contract. Neither the contract nor the Union's constitution or bylaws contained any provision defining or limiting the circumstances under which a member could resign. A few days before the collective agreement expired, the Union membership voted to strike if no agreement was reached by a given date. No agreement was reached in the specified period, so the strike and attendant picketing commenced. Shortly thereafter, the Union held a meeting at which the membership resolved that any member aiding or abetting the employer during the strike would be subject to a $2,000 fine.
About six weeks later, two members sent the Union their letters of resignation. Six months or more later, 29 other members resigned. These 31 employees returned to work.
The Union gave them notice that charges had been made against them and that on given dates the Union would hold trials. None of the 31 employees appeared on the dates prescribed; but the trials nonetheless took place even in the absence of the employees and fines were imposed on all. Suits were filed by the Union to collect the fines. But the outcome was not determined because the employees filed unfair labor practice charges with the National Labor Relations Board against the Union.
The unfair labor practice charged was that the Union restrained or coerced the employees “in the exercise of the rights guaranteed in section 7.” See § 8 (b)(1) of the Act. The Board ruled that the Union had violated § 8 (b)(1). 187 N. L. R. B. 636. The Court of Appeals denied enforcement of the Board’s order. 446 F. 2d 369. The case is here on certiorari, 405 U. S. 987.
We held in NLRB v. Allis-Chalmers Mfg. Co., 388 U. S. 175, that a union did not violate §8 (b)(1) by fining members who went to work during a lawful strike authorized by the membership and by suing to collect the fines. The Court reviewed at length in that opinion the legislative history of §§ 7 and 8(b)(1), and concluded by a close majority vote that the disciplinary measures taken by the union against its members on those facts were within the ambit of the union’s control over its internal affairs. But the sanctions allowed were against those who “enjoyed full union membership.” Id., at 196.
Yet when a member lawfully resigns from the union, its power over him ends. We noted in Scofield v. NLRB, 394 U. S. 423, 429, that if a union rule “invades or frustrates an overriding policy of the labor laws the rule may not be enforced, even by fine or expulsion, without violating §8 (b)(1).” On the facts, we held that Scofield) where fines were imposed on members by the union, fell within the ambit of Allis-Ghalmers. But we drew the line between permissible and impermissible union action against members as follows:
. . §8 (b)(1) leaves a union free to enforce a properly adopted rule which reflects a legitimate union interest, impairs no policy Congress has imbedded in the labor laws, and is reasonably enforced against union members who are free to leave the union and escape the rule.” Id., at 430.
Under § 7 of the Act the employees have “the right to refrain from any or all” concerted activities relating to collective bargaining or mutual aid and protection, as well as the right to join a union and participate in those concerted activities. We have here no problem of construing a union’s constitution or bylaws defining or limiting the circumstances under which a member may resign from the union. We have, therefore, only to apply the law which normally is reflected in our free institutions— the right of the individual to join or to resign from associations, as he sees fit “subject of course to any financial obligations due and owing” the group with which he was associated. Communications Workers v. NLRB, 215 F. 2d 835, 838.
The Scofield case indicates that the power of the union over the member is certainly no greater than the union-member contract. Where a member lawfully resigns from a union and thereafter engages in conduct which the union rule proscribes, the union commits an unfair labor practice when it seeks enforcement of fines for that conduct. That is to say, when there is a lawful dissolution of a union-member relation, the union has no more control over the former member than- it has over the man in the street.
The Court of Appeals gave weight to the fact that the resigning employees had participated in the vote to strike. We give that factor little weight. The first two members resigned from the Union from one to two months after the strike had begun. The others did so from seven tó 12 months after its commencement. And the strike was still in progress 18 months after its inception. Events occurring after the calling of a strike may have unsettling effects, leading a member who voted to strike to change his mind. The likely duration of the strike may increase the specter of hardship to his family; the ease with which the employer replaces the strikers may make the strike seem less provident. We do not now decide to what extent the contractual relationship between union and member may curtail the freedom to resign. But where, as here, there are no restraints on the resignation of members, we conclude that the vitality of § 7 requires that the member be free to refrain in November from the actions he endorsed in May and that his § 7 rights are not lost by a union’s plea for solidarity or by its pressures for conformity and submission to its regime.
Reversed.
Fines equivalent to a day’s wages for each day worked during the strike were imposed.
Section 7 provides in relevant part:
“Employees shall have the right to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection, and shall also have the right to refrain from any or all of such activities ....’’ 61 Stat. 140, 29 U. S. C. §157.
Section 8 (b). “It shall be an unfair labor practice for a labor organization or its agents—
“(1) to restrain or coerce (A) employees in the exercise of the rights guaranteed in section 7: Provided, That this paragraph shall not impair the right of a labor organization to prescribe its own rules with respect to the acquisition or retention of membership therein . . . .” 61 Stat. 141, 29 U. S. C. § 158 (b).
Union-security arrangements requiring employees to pay dues, though not requiring membership, have been held not to be an unfair labor practice and therefore not an excuse for the employer to refuse to bargain collectively for such an agreement, at least where state law allows employees that option. NLRB v. General Motors Corp., 373 U. S. 734.
The Union argues that its practice was to accept resignations of members only during an annual ten-day “escape period,” during which time the employees were allowed to revoke their “dues check-off” authorizations. The Court of Appeals rejected that argument, saying there was no evidence that the employees knew of this practice or that they had consented to its limitation on their right to resign. 446 F. 2d 369, 372.