concurring in the judgment.
The issue here is the proper interpretation of the letters-of-the-carrier and the private mail exceptions to the Private Express Statutes. In reaching a decision we must deal with the Postal Service regulations construing these exceptions; for those regulations, which the majority sets out in its Part II-C, must be respected unless they are inconsistent with the statute — unless either or both are clearly foreclosed by the language or legislative history of the governing statute. If Congress has expressly spoken on the precise issue at hand, the agency must of course not stray from that legislative intent in enforcing the statute. Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837, 842-843 (1984). But if there is more than one rational construction of the statute, the agency’s view should normally be respected.
Here, as I see it, the language of neither exception settles the matter. That should end the inquiry unless the legislative history clearly negates the agency’s view expressed in the regulations. Where the statute itself is not determinative and is open to more than one construction, the legislative history must be quite clear if it is to foreclose the agency’s construction as expressed in its regulations, which is surely not the case here.
Inquiry into that history may lead a court to conclude that the agency’s interpretation is not only permissible but is also the only acceptable construction of the law. But even on the majority’s own description of the statutory background, I am unable to conclude that the agency could not have adopted, and could not now adopt, a view of the exceptions that would, *604on the facts of this case, have reflected the views urged by appellees, particularly with respect to the private mail exception.
Accordingly, I concur in 'the judgment.