They also sugge st that Arizona Sen. John McCain, Bush's main rival for the GOP presidential nomination, may face trouble in coming primaries if he relies too heavily on Democrats and independents, whose votes gave him victories over Bush in New Hampshire and Michigan.

Tuesday was McCain's biggest day of the campaign so far: He won not only the Michigan primary but the one in his home state of Arizona as well.

Among likely Republican voters in California's primary, a Time/CNN poll found Bush leading 48 percent to 23 percent. McCain held a slight but statistically insignificant edge over the Texas governor among Democrats and people without declared party preferences, but only registered Republicans' votes will count in the GOP race anyway.

The poll also found that California Republican voters, when asked which of the two they thought was more likely to win the primary, 60 percent said Bush and 25 percent McCain.

California, the star of the 13-state "Super Tuesday" voting exercise on March 7, awards the winner 162 delegates to this summer's national convention to nominate a candidate. Both Bush and McCain are stepping up their campaigns in the state, with McCain emphasizing his conservative Republican credentials to broaden his base within the party.

A Newsweek magazine poll found Bush enjoying a 56 percent to 27 percent lead nationally among registered Republicans and those likely to vote Republican. It found that 62 percent expected Bush to win the presidential election, down from 73 percent in the last poll in early February, compared with 27 percent for McCain, 8 percentage points above last month's.

And statistics sure to give McCain pause: Only 5 percent of Democratic voters say they will vote or have voted in a Republican primary or caucus, and independents likely to vote in GOP primaries favored Bush by 50 percent to 40 percent.

The Time/CNN poll involved 1,009 likely California primary voters, contacted Thursday and Friday, and has a margin of error of plus or minus 3.1 percentage points. Newsweek surveyed 750 people on the same two days, with an error margin of 4 percentage points.

Another poll, by ABC News, found that despite McCain's surge in prominence of recent weeks, two-thirds of Americans still know little about him.

Only a fourth of Americans consider McCain a conservative, while almost half view him as a moderate and another fourth view him as either a liberal or don't know where he stands. McCain says he is a conservative, and his voting record in many areas has been conservative.

And while McCain's moderate image has given him problems drawing Republican support, he shows great potential for crossover votes, with four in 10 Democrats and liberals alike saying they would seriously consider supporting him. Just over half of Americans, 51 percent, say the more they hear about McCain the more they like him, while a third disagreed with that statement.

The ABC national poll of 509 adults was taken Thursday and has an error margin of plus or minus 4.5 percentage points.