THE SUPREME COURT'S decision on nuclear regulation is clearly going to make it harder to build reactors in this country. Congress could void the decision by changing the law, but that isn't likely. A political deadlock has developed on all the hard choices in energy policy. So far this week, in addition to the reactor decision, there has been the vote in the Senate Energy Committee to do nothing on natural gas deregulation. And the promoters of the Northern Tier Pipeline, to carry Alaskan oil to the Midwest, have now decided to abandon it.

Energy consumption in the United States has fallen sharply since the peak year of 1979, chiefly because of two recessions. The gigantic systems of production and transmission that keep the country running are all operating well under capacity. The present slack makes it all too easy to turn away from the unpleasant questions about future expansion. The court's decision will deepen a national pattern of procrastination on energy.

The court held unanimously that a state--in this case, California--has the authority to impose its own economic regulations on reactor construction. Here the regulation was a ban on new reactors until the federal government decides how the utilities are to dispose of spent fuel. Safe disposal is not difficult as a technical matter, but locating the repositories has political aspects that no one seems very eager to deal with. Congress enacted legislation last year that sets up a process for finding solutions, but those solutions still lie a long way down the road.

If the country is drawing back from nuclear technology, how does it want to generate the electricity that has become a necessity of its life? California has frequently given the impression that its preferred method is to build generating plants in some other state, with a prevailing wind to blow the smoke eastward. The demand for electric power is certainly going to rise. Even if it rises only slowly, the power industry is going to have to keep building new plants to replace old ones as they wear out.

For very good reason, the country has been discouraging the use of oil to generate electricty. As for natural gas, there are better ways to use it. That leaves coal.

The common assumption seems to be that nuclear power is dangerous while coal, if dirty, is safe. Unfortunately, that's not quite right. Thousands--and according to some estimates tens of thousands--of people die prematurely every year because of air pollution from coal-fired power plants. Of all the competing technologies to generate electricity, the country has apparently decided to depend increasingly on the most dangerous. Speaking of political deadlock, you may also have noticed that Congress hasn't made much progress with the reauthorization of the Clean Air Act.