THE SENATE TOOK another whack at federal regulation the other day. This one was notable because it involved a landmark law, the surface mining control and reclamation law that was enacted after years of struggle in 1977. The Senate did not repeal the strict environmental standards for strip mining set forth in the law. But it certainly undermined the whole program by voting, by a sizable margin, to let the states ignore the Interior Department's rules in deciding how those standards should be interpreted and applied.

For many senators, the vote was mainly a rebuke of Interior -- and the department has certainly invited one. After making a number of compromises to get the 1977 law through, critics of strip mining looked to Interior to recapture as much ground as possible in the rules. The agency has not disappointed them. Its regulations, which have been bitterly contested, are very tough and so detailed as to curtail coal production and deny the states even the little leeway that Congress agreed to grant. The Office of Surface Mining has given more ammunition to its critics by being peremptory in some of its dealings with the states -- including those that are trying hard to carry out the law.

But none of that justifies the Senate's action last week. It let its annoyance with these rules and this agency override the fact that a vital program requires some federal supervision and consistent rules. The strip-mining law is more specific than many statutes produced by Congress recently. Still, as Sens. John Melcher (D-Mont.) and Malcolm Wallop (R-Wyo.) tried to remind their colleagues, some crucial aspects of it are not fully defined. Letting each state make its own interpretations would invite political bargains, even more arbitrary federal intervention, and state-by-state litigation without end. The result in some places would be less careful mining -- and in others, less mining of any kind. That's why it was so unfortunate that many usually thoughtful senators voted for this destructive bill. They may be hoping to make the strip-mining program work better, but they are playing into the hands of those who don't want it to work at all.