Less than three weeks ago, the Texas governor led McCain by 40 percentage points in the Field Poll. The survey released today shows Bush ahead 46 percent to 27 percent. Republicans Alan Keyes and Steve Forbes drew 4 percent and 1 percent, respectively.

The survey was conducted just after McCain's decisive victory Tuesday over Bush in the New Hampshire primary.

It also shows McCain in a statistical tie with Vice President Al Gore in a potential general election matchup in California, and comfortably ahead of Gore's Democratic rival, Bill Bradley.

Aides to the Arizona senator, who is campaigning here today in advance of Michigan's primary Feb. 22, said the survey results bolstered their contention that Bush is beatable.

"Before the New Hampshire primary, a lot of California Republicans thought there was only one candidate in the race," said McCain spokesman Todd Harris. "Since then, a lot of them have gotten their first look at John McCain, and so far they like what they see."

McCain attributed the California surge to state residents tuning in to the race after New Hampshire.

"I don't know what else it could be," he said aboard his campaign bus today.

A Bush spokeswoman said the poll's findings were unsurprising.

"We were ahead 40 points before, and we knew that was a lead that wasn't realistic, that couldn't be sustained," said Margita Thompson, California spokeswoman for Bush.

"It's something that is energizing, because as the polls become closer, it has enthused people and energized them to get mobilized," she said.

The poll appears to reflect momentum McCain has built in the nation's largest state in recent days. More than 1,000 California Republicans gave him a hero's welcome at the GOP state convention last weekend. Bush skipped the gathering.

The poll showed Bush slipping against Gore. The two were statistically tied last month, but Gore now leads, 49-42 percent. The Texas governor and Bradley remain locked in a statistically insignificant tie.

The poll is significant because California carries more delegates to the parties' nominating conventions than any other states. The California primary is one month from today.

The Field Poll mirrors surveys in other key states that show McCain cutting deeply into Bush's lead.

It also showed Gore has widened his lead over Bradley among Democrats slightly, and now has a 54-13 percent advantage.

In a hypothetical November contest between McCain and Gore, the two men are statistically tied, 45-44 percent. McCain would beat Bradley, a former New Jersey senator, 46-36 percent.

In a test of preferences pitting all the candidates against one another, Gore carried 30 percent of likely California voters, Bush 23 percent, McCain 15 percent and Bradley 8 percent.

The Field Poll was conducted from Wednesday to Sunday. It surveyed 775 likely voters selected in proportion with the state's registration breakdown.

The margin of error among likely voters was plus or minus 3.5 percentage points. Among likely Democratic voters, the margin was plus or minus 5.5 percentage points, and among likely GOP voters, it was 6 points.