THE drive to limit lawmakers' terms - potentially one of the most potent political movements of the 1990s - is gathering momentum and instilling fresh fears in officeholders from Washington, D.C., to Washington state.Seeking to capitalize on growing mistrust of politicians, groups pushing term limits for state lawmakers and in some cases members of Congress now have ballot campaigns in at least 12 states. They received a significant boost last week when the California Supreme Court upheld most of the provisions of a far-reaching legislative term-limit measure - the first major court test of the constitutionality of such a law. The California decision "gives legitimacy to the [term limits] movement ... [and] is a signal to other state legislatures not to fight them," says Thomas Cronin, acting president of Colorado College and a political science professor. Unless the ruling is overturned, no current legislator in California's 120-member body will be allowed to hold the same office past 1999. So far voters in three states have passed term-limit measures: California, Colorado, and Oklahoma. California's Proposition 140, passed by voters last November, limits statewide officeholders and state senators to two four-year terms. State Assembly members can serve three terms of two years each. Lawyers for the state Legislature, who challenged the constitutionality of the law, plan to appeal the ruling to the US Supreme Court. They argued the initiative infringed on candidates' constitutional rights to run for office and voters' rights to choose such candidates. In rejecting that argument, Chief Justice Malcolm M. Lucas wrote of the state's "strong interests in protecting against an entrenched, dynastic legislative bureaucracy." Proponents predict a new crop of "citizen" politicians will take office as a result of the law. They see term limits as an antidote to the excessive concentration of power in "career politicians." Opponents say term limits throw out good lawmakers with the bad, make politics less attractive to both newcomers and careerists because of the limit on tenure, and decimate the ranks of institutional memory. "California is cleaning house, but who will move in?" asks Sherry Jeffe, a political scientist at the Claremont Graduate School. "The new folks will have to rely heavily on the permanent bureacracy, legislative staff, and lobbyists - none of whom are accountable to the public." The court's ruling will add intensity to debates welling up across the land. On Nov. 5, voters in Washington state will take up the nation's most severe term-limit measure, which provides no exceptions for people in office at the time of the referendum. Legislators would have to leave office in 1994 if they had met or exceeded the limits: three two-year terms for the US House of Representatives or state House; two six-year terms for senators, and two four-year terms for the governor. The entire congressional delegation - including House Speaker Thomas Foley - could be thrown out three years after the vote. "Washington State is the watershed," says Linda Rogers-Kingsbury, head of Let the People Decide - Americans for Ballot Freedom, an anti-term-limit group in Washington, D.C. The state has the only ballot vote this year and the public is now more informed about the issue. Polls show the initiative there leading with a 68 percent approval rating by registered voters. Moreover, many analysts note that there is now more anger than ever at incumbent politicians. At the national level, they cite the Keating Five scandal, congressional check bouncing, and self-imposed pay raises. But whether a state has the right to limit a federal lawmaker's term is expected to be challenged in court. The only other way to limit federal lawmakers' tenures would be a constitutional amendment requiring a two-thirds vote in both House and Senate and three-fourths votes in 34 state legislatures. "That is not likely to happen," says Steve Schier, a professor of political science at Carleton College. Still, proponents of term limits - including conservatives and antitax groups - hope to build momentum at the state level and eventually see federal caps. "Every time congressional members kite checks or run up bills in the restaurant, it is a reminder that it is time for term limits," says Ladonna Lee, a board member of Americans to Limit Congressional Terms. Critics of the California decision see the high court as conservative and Prop. 140 as unusual. "I don't think you should consider the California court decision the last word," says Donald Verrilli, a lawyer representing the National Conference of State Legislatures, one of the groups opposed to term limits. "We think our First Amendment arguments are very strong, and we are going to press them in other courts." Opponents of term limits - including many politicians, academicians, and labor groups - are pursuing a strategy that says: If you're mad at politicians, vote them out. Don't toss everyone out and "ruin" the system.