THE increasingly conservative bent of the United States Supreme Court is shifting the battleground on civil rights issues back to state courts and legislatures.The movement of power from Washington back to the states is all the more ironic because it has been launched by the same institution that radically altered state-federal relations in the 1930s under President Franklin D. Roosevelt's New Deal. Back then, many of the issues were economic and commercial: Could the federal government intervene in the national economy to set agricultural prices, regulate working conditions for coal miners, set the price of coal, and set up a retirement system for railroad employees? A conservative-dominated Court said no, throwing a monkey wrench into many of FDR's economic-recovery programs. The conservative Court also refused to impose many protections of the federal Constitution on state courts and constitutions. It said the 14th Amendment, which guarantees the rights of citizenship and due process, did not apply to the Texas Democratic Party, which excluded blacks from membership so they could not vote in the party primary. In a one-party state like Texas, winning the primary was tantamount to winning the election. Even so, the Court began to extend many constitutional protections even before it turned liberal with the appointment of Justice Hugo Black in 1937. It extended defendants' rights to an attorney and to a fair trial by a fair jury in the famous Scottsboro cases to state trials as well as federal ones. It refused to allow Minnesota to penalize newspapers for criticizing public officials. This tendency received a significant boost with Justice Black's appointment. In short order, the Court upheld many of the same New Deal laws it had only recently struck down. It expanded the federal government's authority to regulate the national economy under the Constitution's interstate-commerce clause and began to define personal rights as more important than property rights. The trend reached its zenith under Chief Justice Earl Warren, who served from 1953 to 1969. The Court upheld the federal government's power to intervene directly against state laws discriminating against blacks; greatly expanded privacy rights, including the right to use contraceptives; broadened the rights of criminal defendants in the Miranda ruling; and engineered a transfer of power in statehouses nationwide by forcing redistricting with its "one person, one vote" ruling. But the liberal Court's use of its decisions to radically alter social and racial policies in the face of stiff opposition from state and local politicians offended many. President Nixon hoped to put an end to the trend, but the Court under his chief justice, Warren Burger, instead continued it with liberal rulings such as the Roe v. Wade decision, which legalized abortion in the first trimester of pregnancy, after state after state had refused to do so. Only the appointees of Presidents Reagan and Bush have succeeded in moving the Court back to a conservative course. This trend was effectively sealed with the confirmation of Justice David Souter last year. It probably constitutes the biggest sea change in the Court's direction since that of 1937. In the areas of civil and defendants' rights, the Court during the last six months has made the change in direction clear. But all may not be lost for liberals. The effect of many of the Court's decisions has been simply to rule that the US Constitution permits police or government actions. But it has left open the possibility that state laws or constitutions may hew to a different standard than does the US Supreme Court. Thus, certain rights and privileges could be strengthened in state constitutions to make up for their loss at the federal level. This would, of course, be the direct opposite of the tenor of federal-state relations over the last 50 years, but given the liberal control of several state legislatures, it is not an unthinkable outcome. The effect of such a development in the current controversy over abortion could be very significant. While the latest nominee for Supreme Court justice, Clarence Thomas, has not yet made clear his views on the abortion issue, many observers say that the Roe v. Wade decision is in more danger than it was before liberal Justice Thurgood Marshall retired. Several abortion-law cases that would give the High Court the opportunity to affirm or overturn Roe v. Wade are currently working their way through the appellate system. If the Supreme Court does overrule Roe v. Wade, the manner in which it does so will be crucial for pro-choice advocates. If it simply returns to the pre-1973 status quo, and leaves the decision on legalization of abortion up to the states, the chances are that many state legislatures would vote to legalize it in some way. It is also possible that in other states, voters would do so in referendums. In states such as Utah and Louisiana, abortion will probably be outlawed. If the High Court rules, however, that a fetus is a person, that abortion is murder, and that no state can therefore sanction it, a political donnybrook is certain to ensue at the federal level as well, as pro-choice proponents struggle to reinstate abortion rights through legislation or a constitutional amendment. This latter course would again involve state legislatures. Regardless of how the Court rules, one thing is certain. As the debate returns to state capitals, there are going to be a lot of uncomfortable local politicians during the next decade. The results could lead to profound changes in American politics.