After conciliation efforts failed, the employees filed a class action in District Court in 1973 charging petitioners with racial discrimination in violation of Title VII and 42 U. S. C. § 1981. Their suit was consolidated for trial with a subsequent Title VII action filed by the EEOC alleging both race and sex discrimination. Following trial, the District Court held that petitioners' seniority, promotion, and job classification practices violated Title VII. The court found that six of the nine lines of progression were not justified by business necessity and "perpetuated past discrimination on the basis of sex and race." App. 32. The court enjoined the company and the union from further use of the six lines of progression. The Court of Appeals for the Fourth Circuit affirmed and remanded for further proceedings with respect to remedy, Patterson v. American Tobacco Co., 535 F. 2d 257 (1976), and we denied a petition for certiorari. 429 U. S. 920 (1976).

On remand petitioners moved to vacate the District Court's 1974 orders and to dismiss the complaints on the basis of this Court's decision in Teamsters v. United States, 431 U. S. 324 (1977), which held that § 703(h) insulates bona fide seniority systems from attack even though they may have discriminatory impact on minorities. The District Court denied the motions, holding that petitioners' seniority system "is not a bona fide system under Teamsters... because this system operated right up to the day of trial in a discriminatory manner." App. 110. A divided panel of the Court of Appeals agreed that "Teamsters requires no modification of the relief we approved with regard to . . . lines of progression. because they were not part of a seniority system within the meaning of § 703(h). 586 F. 2d 300, 303 (1978).

The Court of Appeals reheard the case en banc. It did not decide whether the lines of progression were part of a seniority system. Instead, it held that even if the lines of progression were considered part of a seniority system, "Congress intended the immunity accorded seniority systems by

§ 703(h) to run only to those systems in existence at the time of Title VII's effective date, and of course to routine post-Act applications of such systems." 634 F. 2d 744, 749 (1980).2 We reverse.

II

Petitioners argue that the plain language of § 703(h) applies to post-Act as well as pre-Act seniority systems. The respondent employees claim that the provision "provides a narrow exemption [from the ordinary discriminatory impact test] which was specifically designed to protect bona fide seniority systems which were in existence before the effective date of Title VII." Brief for Respondent Patterson et al. 29. Respondent EEOC supports the judgment below, but urges us to interpret § 703(h) so as to protect the post-Act application of a bona fide seniority system but not the post-Act adoption of a seniority system or an aspect of a seniority system.

As in all cases involving statutory construction, “our starting point must be the language employed by Congress," Reiter v. Sonotone Corp., 442 U. S. 330, 337 (1979), and we assume "that the legislative purpose is expressed by the ordinary meaning of the words used." Richards v. United States, 369 U. S. 1, 9 (1962). Thus "[a]bsent a clearly expressed legislative intention to the contrary, that language must ordinarily be regarded as conclusive." Consumer Product Safety Comm'n v. GTE Sylvania, Inc., 447 U. S. 102, 108 (1980). The plain language of § 703(h) is particularly cogent in light of the circumstances of its drafting. It was part of the Dirksen-Mansfield compromise bill which represented "not merely weeks, but months of labor." 110 Cong. Rec. 11935 (1964) (remarks of Sen. Dirksen). As Senator

"The en banc court remanded the case to the District Court for additional proceedings to determine whether the plantwide seniority system in effect since 1963 is a bona fide seniority system within the contemplation of § 703(h). See 634 F. 2d, at 750. This issue is not before the Court.

Dirksen explained: "I doubt very much whether in my whole legislative lifetime any measure has received so much meticulous attention. We have tried to be mindful of every word, of every comma, and of the shading of every phrase." Ibid. On its face § 703(h) makes no distinction between pre- and post-Act seniority systems, just as it does not distinguish between pre- and post-Act merit systems or pre- and post-Act ability tests. The section does not take the form of a saving clause or a grandfather clause designed to exclude existing practices from the operation of a new rule. Other sections of Title VII enacted by the same Congress contain grandfather clauses, see § 701(b), 78 Stat. 253, as amended, 42 U. S. C. § 2000e (b), a difference which increases our reluctance to transform a provision that we have previously described as "defining what is and what is not an illegal discriminatory practice. ," Franks v. Bowman Transportation Co., 424 U. S. 747, 761 (1976), from a definitional clause into a grandfather clause.

...

The EEOC's position, which is urged by JUSTICE BRENNAN's dissent, is no more supportable. In permitting an employer to "apply" different terms of employment pursuant to a seniority system, § 703(h) does not distinguish between seniority systems adopted before and those adopted after the effective date of the Act. That distinction would require reading § 703(h) as though the reference to a seniority system were followed by the words "adopted prior to the effective date of this section." But the section contains no such limitation. To be cognizable, a claim that a seniority system has a discriminatory impact must be accompanied by proof of a discriminatory purpose.

Furthermore, for the purpose of construing § 703(h), the proposed distinction between application and adoption on its face makes little sense. The adoption of a seniority system which has not been applied would not give rise to a cause of action. A discriminatory effect would arise only when the system is put into operation and the employer "applies” the

system. Such application is not infirm under § 703(h) unless it is accompanied by a discriminatory purpose. An adequate remedy for adopting a discriminatory seniority system would very likely include an injunction against the future application of the system and backpay awards for those harmed by its application. Such an injunction, however, would lie only if the requirement of § 703(h)—that such application be intentionally discriminatory-were satisfied.

Under the EEOC's interpretation of the statute, plaintiffs who file a timely challenge to the adoption of a seniority system arguably would prevail in a Title VII action if they could prove that the system would have a discriminatory impact even if it was not purposefully discriminatory. Post, at 86. See Griggs v. Duke Power Co., 401 U. S. 424 (1971). On the other hand, employees who seek redress under Title VII more than 180 days after the adoption of a seniority system-for example, all persons whose employment begins more than 180 days after an employer adopts a seniority system-would have to prove the system was intentionally discriminatory. Yet employees who prevailed by showing that a bona fide seniority system had a discriminatory impact although not adopted with discriminatory intent would not be entitled to an injunction forbidding the application of the system: § 703(h) plainly allows the application of such a seniority system.

'Prior to 1972, Title VII generally required charges to be filed within 90 days of an alleged discriminatory practice. Section 706(e), 78 Stat. 260, was amended in 1972. It now requires aggrieved persons to file a charge "within one hundred and eighty days after the alleged unlawful employment practice occurred. . . ." 42 U. S. C. § 2000e−5(e).

'The facts of this case give rise to just such an anomaly under the EEOC theory. The respondent employees filed race discrimination charges within 90 days of the adoption of the lines of progression but sex discrimination charges were filed more than 90 days after the adoption. Under the EEOC theory, the lines of progression would be analyzed under two different tests: the Griggs impact test and the § 703(h) intentional discrimination test.

A further result of the EEOC's theory would be to discourage unions and employers from modifying pre-Act seniority systems or post-Act systems whose adoption was not timely challenged. Any modification, if timely challenged, would be subject to the Griggs standard-even if it benefited persons covered by Title VII-thereby creating an incentive to retain existing systems which enjoy the protection of §703(h).5

Statutes should be interpreted to avoid untenable distinctions and unreasonable results whenever possible. The EEOC's reading of § 703(h) would make it illegal to adopt, and in practice to apply, seniority systems that fall within the class of systems protected by the provision. We must, therefore, reject such a reading.

III

Although the plain language of § 703(h) makes no distinction between pre-Act and post-Act seniority systems, the court below found support for its distinction between the two in the legislative history. Such an intepretation misreads the legislative history.

We have not been informed of and have not found a single statement anywhere in the legislative history saying that § 703(h) does not protect seniority systems adopted or modified after the effective date of Title VII. Nor does the legislative history reveal that Congress intended to distinguish between adoption and application of a bona fide seniority system. The most which can be said for the legislative history of § 703(h) is that it is inconclusive with respect to the issue presented in this case."

"Significant freedom must be afforded employers and unions to create differing seniority systems." California Brewers Assn. v. Bryant, 444 U. S. 598, 608 (1980). Respondents' interpretation of § 703(h) would impinge on that freedom by discouraging modification of existing seniority systems or adoption of new systems.

'JUSTICE BRENNAN's dissent admits that the legislative history "does not contain any explicit reference to the distinction between adoption and