THERE IS A CLEAR warning to local governments and taxpayers in the Supreme Court's decision last Tuesday that a school board can be sued for damages if its official policy injures someone's rights. For the governments, the message is that they had better be more careful about the laws they pass and the policies they adopt or they may get hit with some big damage suits. For the taxpayers, it is that someone may have to pay the bills for dumb or careless or lawless decisions by local officials * - and that "someone" will be you.

This change from the past may have unpleasant repercussion in some communities. It means that if a school board adopts a policy infringing the rights of a student, teacher or someone else, the taxpayers will have to come up with the money to repair the damage done. Previously, school boards were immune from damage suits, although the courts could force them to change any illegal policies. For example, a teacher who is compelled to take an unpaid leave of absence soley because she is pregnant (without regard to her medical condition) can now collect back pay; before last Tuesday, all she could hope for from the federal courts was a declaration that the school board's policy was illegal.

There are many other situations in which school boards have trampled on the rights of individuals in the past without having to fear anything more than a judicial order to stop. The most prominent of these, of course, involves racial segregation. Students who are victims of a school board's segregationist policies will now be in position to claim damages as well as try to get those policies changed. It doesn't take much imagination to figure out what the effect on the budgets of some communities would have been in the last 20 years if black students had been collecting damages as well as opening schoolhouse doors.

That doesn't mean that, in an era of rapidly changing law, all school boards that transgress on someone's rights would be liable for damages. The court may well decide - it specifically left the question open - that a school board is liable only if its actions were clearly illegal when they were taken. If the court chooses that course, a board that had a policy of sending home pregnant teachers of assigning students by race would be able to avoid paying damages by changing the policy as soon as the courts ruled it was illegal.

While the court left open the question of what other units of local government will also lose their immunity to suits of this kind, the obvious answer seems to be: most of them. The logic of the court's opinion requires the stripping of immunity from all governmental units below the state level; states, of course, are guaranteed continued immunity by the Consititution. That means, among other things, that prisoners in local jails and inmates in local hospitals will soon be seeking compensation if they are mistreated as a result of rules or officials policies. In the past, they won damages only if they had been mistreated by individual officials acting without official sanction. Even then, the awards were against those officials and not the local governments (and taxpayers).

Regardless of how the court handles these subsidiary questions, this recent decision should cause local governments to act with a little more caution on matters touching civil rights. It will take only one round of damage suits - say, $25,000 against a small town because its parade permit policy was patently unconstitutional - before taxpayers and voters begin to understand that a government that ignores the law or is careless in what it does can run up their tax bills just as can one that is only profligate.