By Daniel Trotta

NEW YORK (Reuters) - Republican New Jersey Governor Chris Christie could be about to turn down his best chance of becoming U.S. president, saying "no" just when his political fortunes may be at their peak.

Privately and publicly, influential Republicans are urging Christie to run and are prepared to raise money. That's because Democratic President Barack Obama is politically vulnerable with little prospect for an ascendant economy to provide a boost before the November 2012 election and none of the current Republican candidates have distanced themselves from the field.

Yet Christie has insisted repeatedly and in the clearest terms that he will not run in 2012.

"When it comes to running for president, you don't pick the time. The time picks you," said Patrick Murray, director of the Monmouth University Polling Institute in New Jersey. "If his burning desire is to be president, then the time is now. You don't know what the environment will be in 2016 or 2020."

Christie has yet to display even a flickering desire, repeating many times that he is not interested. Sometimes he says it with candor ("I'm not ready"), sometimes with humor ("What, short of suicide, do I have to do to convince people I'm not running?")

Christie, who was elected governor in 2009, was on a Republican Party fund-raising tour with stops in Missouri and California, including a speech at the Ronald Reagan Presidential Foundation & Library on Tuesday night, which only heightened speculation he might change his mind. Excerpts released ahead his speech made no mention of presidential intentions.

"This is a do or die moment for him," said Brigid Harrison, a professor of political science and law at New Jersey's Montclair State University.

"There is a risk in waiting," she said, because by 2016, "he won't be the new kid on the block anymore."

WOOED BY WALL STREET

Many Republicans liked Christie's combative stand against public sector unions, which led to cost-cutting deals that helped balance New Jersey's budget while putting a cap on property taxes. A former federal prosecutor, Christie appeals to law-and-order conservatives but is moderate enough on social issues that he was able to win in a Democratic-leading state.

Despite Christie's avowed disinterest in the White House, long-time adviser Tom Kean gave the Christie-for-president movement a boost Monday when he said Christie was "very seriously" considering running.

"He's giving it a lot of thought. I think the odds are a lot better now than they were a couple weeks ago," Kean, a former New Jersey governor, told the National Review Online.

Wall Street Republicans in particular have been urging him to run. Three politically connected Republicans in the financial industry told Reuters on Tuesday he was being courted by activists who are dissatisfied with the current Republican field, but they asked not to be identified by name.

The New York Times listed a number of wealthy and influential party activists who were trying to get him to run, including David Koch, recently listed by Forbes magazine as the richest New Yorker, and hedge fund magnate Paul Singer.

The New York Post Republican royalty such as former first lady Barbara Bush and former Secretary of State Henry Kissinger were wooing Christie.

Dante Scala, chair of the Department of Political Science at the University of New Hampshire, said elites want Christie because they "feel they can do business with him."

Looking at the presumed front-runners, they do not see former Massachusetts Governor Mitt Romney as a real conservative and do not trust Texas Governor Rick Perry, Scala said. They see the others as fringe candidates who cannot beat Obama.

"It's always what you cannot have that you want the most," Scala said.

Christie still has time to change his mind but not much. The deadline for registering for the Florida primary is October 31.

(Additional reporting by Dave Warner, Edith Honan and Mark Egan; Editing by Bill Trott)