MANCHESTER, New Hampshire -- If New Jersey Gov. Chris Christie enters the 2012 presidential race, he could dramatically reshape what has become a two-man race between Mitt Romney and Rick Perry.
But Christie, who's under pressure from some party elders to run, hasn't faced national scrutiny - and he could join other early favorites who burned out fast.
The budget-cutting Christie is the latest heartthrob of Republicans who have been looking for a more exciting candidate than Romney. The former Massachusetts governor ran in 2008 and has long been considered the one to beat for the Republican nomination given the party's history of nominating candidates who lost once before.
Indiana Gov. Mitch Daniels, a favorite of fiscal conservatives, decided not to run. So did Mississippi Gov. Haley Barbour, long a part of the Republican establishment.
Perry, the Texas governor, jumped in to much fanfare only to sweat under the scrutiny his first national campaign brought. Minnesota Rep. Michele Bachmann rallied restive conservatives long enough to win a key test vote in the Iowa straw poll but just as quickly receded to the background.
Christie said in January he wasn't "arrogant enough" to run for president in 2012. Now he is reconsidering in light of encouragement from Republican luminaries like Henry Kissinger, Nancy Reagan and Barbara Bush.
If he runs, Christie probably would be able to raise millions for a campaign, though his rivals have a huge head start. With about 100 days before the lead-off caucuses in Iowa, he'd face the tough task of setting up state campaign organizations swiftly, though he already has a team of advisers with national campaign experience.
As a Republican governor of a Democratic mid-Atlantic state, he could appeal to the donors and voters who like Romney's business background but are looking for a more charismatic candidate.
If he does run, Christie would push a long list of second-tier candidates even further to the back of the pack. Still, some positions he's taken as New Jersey governor could run afoul of conservatives who make up the Republican base.
He would also face a national spotlight that's much harsher than those on the state or local stage.
"The swimming pool looks a lot better until you jump right in. The water may not be quite as warm as you think," Sen. John McCain, the Republican nominee in 2008, warned Sunday on CBS television's "Face the Nation."
"The best thing to be is a potential candidate," said Rich Galen, a longtime Republican strategist. "I don't think anybody can stand up to that scrutiny without laying the groundwork for a long time before. ... His positions, whatever he's done as a prosecutor, any case he's ever tried, any opinion he's ever gotten out of a judge, everything - it's all going to go under scrutiny that we've seen time after time is enormously more difficult to deal with as a presidential candidate."
Just ask Perry. Two months ago, Republicans were pushing him to run. He shot to the top of national polls of Republican voters after his announcement in mid-August. He was lauded as the kind of candidate who could energize a passionate base of social conservatives and lure business conservatives.
A few shaky debate performances and many attacks from Romney later, Perry has already begun to fade. His weaknesses were on stark display this weekend in New Hampshire, where he held a series of town hall meetings and was asked over and over again about a bill he signed that allows illegal immigrants to receive lower in-state tuition at Texas universities.
Other questioners wanted to know how he would help senior citizens after he called Social Security a "Ponzi scheme." Romney signs and mocking campaign literature greeted him at almost every stop.
Perry aides point to the fact that he has been running for about six weeks, while Romney has been preparing his second presidential bid since the first one ended. But they acknowledge that starting later has made Perry's path more difficult - and while they insist immigration and Social Security are much less important issues than the economy and jobs, they also say Christie could face similar problems.
"I don't actually know where (Christie) is on abortion and guns and things like that, but there may be people on the conservative side who have problems with that," said David Carney, Perry's top strategist. "The scrutiny that will come on his ideological and fiscal policies and social policies will be magnified greatly because of the short time period."
Christie favors some restrictions on gun rights, as well as civil unions for gay couples. He now opposes abortion, but described himself as "pro-choice" at the beginning of his political career.
All of that will provide plenty of fodder for Romney, whose carefully built, long-running campaign has moved steadily through repeated rounds of doubt and speculation about other candidates. In some cases, he has tweaked his message - downplaying his time as governor to paint Perry as a career politician, for example - but made no major course corrections. While Christie's similar profile threatens Romney more directly, there's no indication Romney plans to make a major shift if Christie jumps in.
"The Romney campaign has been built to withstand all elements and endure every candidate scenario," said Kevin Madden, a senior Romney aide in 2008 who now serves as an informal adviser. "The last nine months have seen a series of `insert name here' candidates, but the campaign has focused relentlessly on the economic message and making the case that Gov. Romney is the best candidate to beat President Obama, and will continue to do so."
And a Christie entry could end up actually helping Romney.
"Everyone will aim at the perceived frontrunner," said Galen, the Republican strategist. "It helps Romney because it will keep the pressure off of him for the next three to four weeks, and depending what happens with the calendar, Romney just has to gather himself and sprint to the finish."
As early as this week, Christie could announce whether he will run and reverse himself after more than a year of ruling out a candidacy. Changes in the primary calendar have left him with much less time to put together a campaign. Christie would have scarcely three months to set up a campaign for the Iowa caucuses, which appear likely to happen in early January. New Hampshire's primary would come soon after.
So far, there's scant evidence that Christie has begun to organize campaigns in the early states. He has some foothold in Iowa, where he campaigned for Republican Gov. Terry Branstad and hosted a fundraiser with Republican Rep. Steve King. A delegation of Iowa donors traveled to New Jersey earlier this year to urge Christie to run.
But top operatives there say they haven't yet heard from Christie's team, and the story is much the same in New Hampshire.
"Gov. Christie would make a compelling candidate for president, but there is no evidence whatsoever that he has reached out to top Republican officials and opinion leaders," said Mike Dennehy, a top New Hampshire Republican strategist who was McCain's political director in 2008.