A LAW PROFESSOR of our acquaintance used to illustrate what he considered the absurdity of Supreme Court antitrust decisions by saying that the principles on which they were based could be used to break up the National Football League. Now there is a decision from the California Supreme Court that threatens to do exactly that. By a 6-to-1 margin, in a decision written by a Reagan appointee, that court has ruled that the city of Oakland may use its power of eminent domain to acquire the Oakland Raiders.

The city brought the suit because the Raiders' principal owner, Al Davis, announced he would move the team to Los Angeles. That would give him access to the nation's second biggest television market and would deprive Oakland's $65 million municipal stadium of its biggest tenant. The state supreme court says the city can seize the team if it fulfills two conditions: first, it must prove that the Raiders contribute to the health and well-being of the community; and second, it must pay a fair market price to the team's current owners. In other words, the city can gain ownership of a major sports team in the same way it can take a vacant lot that it wants for a park.

The court's decision leaves unanswered a lot of questions. Can the Oakland suburb of San Leandro, for example, acquire the Raiders by eminent domain? After all, its citizens derive as much health and well- being from the presence of the Raiders in the general area as most citizens of Oakland do. Can a city acquire a team by eminent domain sometime after it has left for other climes? After all, why should a few days' or even a few years' absence make a difference in the future contribution to a city's health and well-being that a team could make?

We ask these questions from a not entirely disinterested perspective. Some of our older readers may recall that not just one, but two, of the teams now in major league baseball were once called the Washington Senators. We are waiting for one of the candidates for mayor to pledge that he or she, if elected, will bring a lawsuit similar to Oakland's to allow the District of Columbia to acquire ownership of the teams known currently and, we trust, temporarily as the Minnesota Twins and the Texas Rangers. Washington, having done without a major league baseball team for some time now, deserves to have two. We leave for your contemplation the question whether the District government would manage the teams more successfully than their private owners did in the past.