New polls show Mitt Romney in a virtual tie with GOP presidential rival John McCain in two key states with upcoming primaries.

With Tuesday's Florida Republican primary looming, a Miami Herald poll of 800 likely voters showed McCain narrowly leading the Republican field with 25 percent of the vote, followed by Romney with 23 percent. Rudy Giuliani and Mike Huckabee each received 15 percent.

With the margin of error at 5.1 percent, the results place McCain and Romney in a statistical tie.

In California, a new Field Poll shows McCain and Romney faring well and Giuliani tumbling badly with two weeks to go before that state's Feb. 5 primary.

In the survey of likely voters interviewed between Jan. 14-20, McCain led Romney 22 percent to 18 percent. The split between the two tightened when pollsters recalculated after Tuesday's decision by former Tennessee Sen. Fred Thompson to quit the race — 23 percent for McCain to 21 percent for Romney and 13 percent for Giuliani.

Given the poll's margin of error of 5.2 percentage points, the two candidates are essentially even.

Before Thompson's announcement, the Field Poll showed Giuliani and former Arkansas Gov. Mike Huckabee at 11 percent, Thompson at 9 percent and Texas Rep. Ron Paul at 7 percent.

Thompson said Tuesday he was dropping out of the GOP race after a disappointing showing in Saturday's South Carolina primary. So the Field Poll reshuffled its numbers, factoring in voters' stated preferences for their second-choice candidates in the GOP field.

That tightened the outcome to 23 percent for McCain, 21 percent for Romney, 13 percent for Giuliani, 12 percent for Huckabee and 7 percent for Paul. Twenty-three percent of voters remained undecided and 1 percent backed other candidates.

With absentee voting under way in California, Giuliani has plummeted from a high of 37 percent GOP support last March. Meanwhile, McCain has rebounded sharply from a low of 9 percent support in August.

In today's editions, the New York Times also reported that Romney has become the most disliked candidate within the circle of GOP contenders.

"Never get into a wrestling match with a pig," McCain said this month to reporters when asked about Romney.

Huckabee's pugilistic campaign chairman, Ed Rollins, appeared to stop just short of threatening Romney with physical violence.

"What I have to do is make sure that my anger with a guy like Romney, whose teeth I want to knock out, doesn't get in the way of my thought process," Rollins said.

Campaign insiders and outside strategists point to several factors driving the ill will, most notably, the attacks by Romney against his opponents in television commercials, the perception of him as an ideological panderer and resentment about his seemingly unlimited resources as others have struggled to raise cash.

"I think it's largely driven by the fact that everybody's taught to tackle the guy on the field with the ball," Romney spokesman Kevin Madden, said.

"The glee the other candidates go after Romney with is really unique," said Dan Schnur, a Republican strategist who worked on McCain's presidential campaign bid in 2000 but currently is not affiliated with any campaign.

Schnur used a schoolyard analogy to compare Romney, the ever proper Harvard graduate, to McCain, the gregarious rebel who racked up demerits and friends at the Naval Academy.

"John McCain and his friends used to beat up Mitt Romney at recess," Schnur said.

Contributing: Beth Reinhard and Breanne Gilpatrick, McClatchy Newspapers; Peter Hecht, Scripps Howard News Service; Michael Luo, New York Times News Service