IN EDUCATION funding as in much else, the devil lies in the details -- and no more so than in the case of the administration's proposal to pay 90 percent of the costs of educating students displaced by Hurricane Katrina. The administration has provided no more than an outline of what it wants to do. Some narrower proposals about extra funding and loan forgiveness for college students forced to interrupt their studies have already been signed into law. But there is also talk -- still vague -- of spending $7,500 per displaced student, regardless of whether they choose public or private education. As a result, an argument is brewing about whether such a provision would constitute the first national voucher program, and, if so, whether the administration is trying to use the Katrina emergency to put one in place.

As we've said, the details are not available. But while Congress works them out, it's important that lawmakers keep a few principles in mind. The federal government is right to help those states that have had huge influxes of displaced students, but this is not the time to create any kind of large federal schools program, let alone a voucher program: Good federal policy is not going to be made in the wake of a crisis. In the past we have favored vouchers, on a trial basis and as a specific solution to the problems of specific school systems, such as those of the District. By contrast, a federally funded national program would destroy local districts' ability to make their own decisions, and there's no evidence it would help schools or children.

Nevertheless, just as it's important not to sneak in an enormous new federal program for ideological reasons, it's also important that neither Democrats, teachers unions nor anyone else rule out for ideological reasons what could be a useful tool for distributing relief funds. There could be pragmatic reasons to put displaced students in private or parochial schools: if, say, school districts are overcrowded, if students have special needs or if that happens to be where they ended up. So it might make sense to attach a sum to each student -- whether it's called a voucher or something else -- as long as that sum is given out in a limited number of places and for a limited time, certainly not longer than the current school year.

Any "emergency" bill that has the potential to turn into a long-term federal subsidy for private schools must be quashed. But any solution that would allow students to finish the year with a minimum of fuss and disruption to themselves and their families, and that would prevent school districts in Texas and elsewhere from being unduly burdened, should be welcomed.