Sierra Club, for example, attacked the use of the phrase "consistent with the primary purpose" in proposed H. R. 4758, cautioning that the qualification "could be construed to be a declaration of congressional policy that other agency purposes are necessarily more important than protection of endangered species and would always prevail if conflict were to occur." 1973 House Hearings 335 (statement of the chairman of the Sierra Club's National Wildlife Committee); see id., at 251 (statement for the National Audubon Society).

What is very significant in this sequence is that the final version of the 1973 Act carefully omitted all of the reservations described above. In the bill which the Senate initially approved (S. 1983), however, the version of the current §7 merely required federal agencies to "carry out such programs as are practicable for the protection of species listed . . . ." 27 S. 1983, § 7 (a). (Emphasis added.) By way of contrast, the bill that originally passed the House, H. R. 37, contained a provision which was essentially a mirror image of the subsequently passed § 7-indeed all phrases which might have qualified an agency's responsibilities had been omitted from the bill.28 In explaining the expected impact of this provision in H. R. 37 on federal agencies, the House Committee's Report states:

"This subsection requires the Secretary and the heads of all other Federal departments and agencies to use their authorities in order to carry out programs for the pro

27 We note, however, that in the version of S. 1983 which was sent to the floor of the Senate by the Senate Committee on Commerce, the qualifying language "wherever practicable" had been omitted from one part of the bill, that being § 2 (b). See 119 Cong. Rec. 25663 (1973). Section 2 (b) was the portion of S. 1983 that stated the "purposes and policy" of Congress. But the Committee's version of S. 1983-which was reported to the full Senate-retained the limitation on § 7 that we note here. 119 Cong. Rec. 25664 (1973).

28 See id., at 30157-30162.

tection of endangered species, and it further requires that those agencies take the necessary action that will not jeopardize the continuing existence of endangered species or result in the destruction of critical habitat of those species." H. R. Rep. No. 93-412, p. 14 (1973). (Emphasis added.)

Resolution of this difference in statutory language, as well as other variations between the House and Senate bills, was the task of a Conference Committee. See 119 Cong. Rec. 30174-30175, 31183 (1973). The Conference Report, H. R. Conf. Rep. No. 93-740 (1973), basically adopted the Senate bill, S. 1983; but the conferees rejected the Senate version of § 7 and adopted the stringent, mandatory language in H. R. 37. While the Conference Report made no specific reference to this choice of provisions, the House manager of the bill, Representative Dingell, provided an interpretation of what the Conference bill would require, making it clear that the mandatory provisions of § 7 were not casually or inadvertently included:

"[Section 7] substantially amplifie[s] the obligation of
[federal agencies] to take steps within their power to
carry out the purposes of this act. A recent article...
illustrates the problem which might occur absent this new
language in the bill. It appears that the whooping cranes
of this country, perhaps the best known of our endangered
species, are being threatened by Air Force bombing
activities along the gulf coast of Texas. Under existing
law, the Secretary of Defense has some discretion as to
whether or not he will take the necessary action to see
that this threat disappears
[O]nce the bill is
enacted, [the Secretary of Defense] would be required
to take the proper steps. .

"Another example [has] to do with the continental population of grizzly bears which may or may not be endangered, but which is surely threatened. . . . Once this

bill is enacted, the appropriate Secretary, whether of Interior, Agriculture or whatever, will have to take action to see that this situation is not permitted to worsen, and that these bears are not driven to extinction. The purposes of the bill included the conservation of the species and of the ecosystems upon which they depend, and every agency of government is committed to see that those purposes are carried out. . . . [T]he agencies of Government can no longer plead that they can do nothing about it. They can, and they must. The law is clear." 119 Cong. Rec. 42913 (1973). (Emphasis added.)

It is against this legislative background" that we must measure TVA's claim that the Act was not intended to stop operation of a project which, like Tellico Dam, was near completion when an endangered species was discovered in its path. While there is no discussion in the legislative history of precisely this problem, the totality of congressional action makes it abundantly clear that the result we reach today is wholly in accord with both the words of the statute and the intent of Congress. The plain intent of Congress in enacting this statute was to halt and reverse the trend toward species extinction, whatever the cost. This is reflected not only in the stated policies of the Act, but in literally every section of the statute. All persons, including federal agencies, are specifically instructed not to "take" endangered species, meaning that no one is "to harass, harm,[30] pursue, hunt, shoot,

29 When confronted with a statute which is plain and unambiguous on its face, we ordinarily do not look to legislative history as a guide to its meaning. Ex parte Collett, 337 U. S. 55, 61 (1949), and cases. cited therein. Here it is not necessary to look beyond the words of the statute. We have undertaken such an analysis only to meet MR. JUSTICE POWELL'S suggestion that the "absurd" result reached in this case, post, at 196, is not in accord with congressional intent.

30 We do not understand how TVA intends to operate Tellico Dam without "harming" the snail darter. The Secretary of the Interior has defined the term "harm" to mean "an act or omission which actually

153

Opinion of the Court

wound, kill, trap, capture, or collect" such life forms. 16 U. S. C. §§ 1532 (14), 1538 (a)(1)(B) (1976 ed.). Agencies in particular are directed by §§ 2 (c) and 3 (2) of the Act to "use . all methods and procedures which are necessary" to preserve endangered species. 16 U. S. C. §§ 1531 (c), 1532 (2) (1976 ed.) (emphasis added). In addition, the legislative history undergirding § 7 reveals an explicit congressional decision to require agencies to afford first priority to the declared national policy of saving endangered species. The pointed omission of the type of qualifying language previously included in endangered species legislation reveals a conscious decision by Congress to give endangered species priority over the "primary missions" of federal agencies.

It is not for us to speculate, much less act, on whether Congress would have altered its stance had the specific events of this case been anticipated. In any event, we discern no hint in the deliberations of Congress relating to the 1973 Act that would compel a different result than we reach here.31

31

injures or kills wildlife, including acts which annoy it to such an extent as to significantly disrupt essential behavioral patterns, which include, but are not limited to, breeding, feeding or sheltering; significant environmental modification or degradation which has such effects is included within the meaning of 'harm.'" 50 CFR § 17.3 (1976) (emphasis added); see S. Rep. No. 93-307, p. 7 (1973).

31 The only portion of the legislative history which petitioner cites as being favorable to its position consists of certain statements made by Senator Tunney on the floor of the Senate during debates on S. 1983; see 119 Cong. Rec. 25691-25692 (1973). Senator Tunney was asked whether the proposed bill would affect the Army Corps of Engineers' decision to build a road through a particular area of Kentucky. Responding to this question, Senator Tunney opined that § 7 of S. 1983 would require consultation among the agencies involved, but that the Corps of Engineers "would not be prohibited from building such a road if they deemed it necessary to do so." 119 Cong. Rec. 25689 (1973). Petitioner interprets these remarks to mean that an agency, after balancing the respective interests involved, could decide to take action which would extirpate an endangered species. If that is what Senator Tunney meant, his views are in distinct

Indeed, the repeated expressions of congressional concern over what it saw as the potentially enormous danger presented by the eradication of any endangered species suggest how the balance would have been struck had the issue been presented to Congress in 1973.

Furthermore, it is clear Congress foresaw that § 7 would, on occasion, require agencies to alter ongoing projects in order to fulfill the goals of the Act.32 Congressman Dingell's discussion of Air Force practice bombing, for instance, obviously pinpoints a particular activity-intimately related to contrast to every other expression in the legislative history as to the meaning of § 7. For example, when the Kentucky example was brought up in the Senate hearings, an administration spokesman interpreted an analogous provision in S. 1592 as "prohibit [ing] [a] federal agency from taking action which does jeopardize the status of endangered species." Supra, at 179. Moreover, we note that the version of S. 1983 being discussed by Senator Tunney contained the "as practicable" limitation in § 7 (a) which we have previously mentioned. See supra, at 182. Senator Tunney's remarks perhaps explain why the Conference Committee subsequently deleted all such qualifying expressions. We construe the Senator's remarks as simply meaning that under the 1973 Act the agency responsible for the project would have the "final decision," 119 Cong. Rec. 25690 (1973), as to whether the action should proceed, notwithstanding contrary advice from the Secretary of the Interior. The Secretary's recourse would be to either appeal to higher authority in the administration, or proceed to federal court under the relevant provisions of the Act; citizens may likewise seek enforcement under 16 U. S. C. § 1540 (g) (1976 ed.), as has been done in this case.

32 MR. JUSTICE POWELL characterizes the result reached here as giving "retroactive" effect to the Endangered Species Act of 1973. We cannot accept that contention. Our holding merely gives effect to the plain words of the statute, namely, that § 7 affects all projects which remain to be authorized, funded, or carried out. Indeed, under the Act there could be no "retroactive" application since, by definition, any prior action of a federal agency which would have come under the scope of the Act must have already resulted in the destruction of an endangered species or its critical. habitat. In that circumstance the species would have already been extirpated or its habitat destroyed; the Act would then have no subject matter to which it might apply.