SAN JOSE, DEC. 13 -- Political activists who led successful campaigns this year to limit state legislative terms in California, Colorado and Oklahoma said today that they will carry the movement to as many as 20 other states by 1992 and seek to restrict terms of members of Congress.

But participants in the national drive disagreed about the usefulness of President Bush's support for a federal constitutional amendment that would restrict terms of all Senate and House members.

White House Chief of Staff John H. Sununu said Tuesday that Bush will propose such an amendment in his State of the Union message next month.

Los Angeles County Supervisor Pete Schabarum, a principal sponsor of this year's voter-approved Proposition 140 that restricted terms of most California public officials, said an initiative limiting members of Congress and U.S. senators from California to 12 years in office would qualify for the state ballot in 1992.

State Sen. Terry Considine of Denver, who led the campaign for the Colorado initiative that also restricted congressional terms to 12 years, said he expects term-limit measures on as many as 20 state ballots in 1992.

Schabarum and Considine welcomed Bush's participation, but Lewis K. Uhler, president of the National Tax Limitation Foundation, said support by "the 800-pound gorilla in the White House" would give the term-limit issue greater visibility at the cost of risking "a partisan emphasis that we're trying to defuse."

Uhler, also a cosponsor of Proposition 140, joined others here in warning that term limits could be discredited if seen as a partisan Republican issue.

The limits nonetheless could provide an enormous benefit for Republican candidates. Most incumbent legislators, like most incumbent members of Congress, are reelected, while most partisan changes occur in contests for open seats.

Democrats currently control both chambers in 30 of 50 state legislatures, with Republicans controlling only five. Control is split between the parties in 14 states, and Nebraska has a nonpartisan unicameral legislature.

Some Republicans attending the conference said the GOP would benefit particularly from creation of many more open seats.

"It will help in recruitment of good candidates," said Republican political consultant Ken Rietz. "It's hard to get people to run against incumbents who represent safe districts and are sitting on a pile of money."

But several participants at the conference, sponsored by the Washington-based Americans To Limit Congressional Terms, said women and minorities of both parties also would be helped by term limits since they are underrepresented in Congress and most legislative bodies and frequently underfinanced when opposing entrenched incumbents.

Expressing the populist view that restrictions on terms would open up the political system, San Jose Mayor Tom McEnery, a maverick Democrat, said, "I don't like what the two parties stand for. They are an oligarchy of incumbents who are interested in being in office rather than in what they can do when they get there."

Schabarum said he expected the initiative to restrict terms of California's members of Congress would be patterned after the Colorado initiative unless overturned by a court challenge. He said he also anticipated legal challenges to Proposition 140 but expected the measure to survive.

Considine said that, in approving limits on congressional terms, Colorado voters rejected what he called "the scam, the con game" that seniority is needed to "bring back the pork."

As state limitations on congressional terms spread, he said, several of those elected to the reduced terms are likely to become advocates of a federal constitutional amendment restricting congressional service.

The Republican legislative leadership had retaliated against Considine in Colorado, where the GOP controls the legislature, by stripping him of his Finance Committee chairmanship and assigning him to a seat on the Agriculture Committee even though he represents an urban district.