Updated 5:58 p.m. Eastern Time
One week after, New Jersey governor Chris Christie on Tuesday endorsed former Massachusetts governor Mitt Romney.
"America cannot survive another four years of Barack Obama, and Mitt Romney is the man we need to lead America, and we need him now," Christie said at a Romney campaign event in Lebanon, New Hampshire.
Romney "brings that great private sector experience and he brings that experience as governor of Massachusetts knowing how government works," Christie added, telling reporters that his decision to back the Massachusetts governor was "easy."
Mitt and Ann Romney went to Christie's house in New Jersey on Saturday, a senior Romney campaign adviser told CBS News. It was there that Christie said he would endorse Romney.
Suggesting that Romney was the most electable candidate in the field, Christie said that "as Republicans, our number one goal this year has to be to preserve our American way of life."
Romney "has laid out the most detailed economic plan of anybody in the race," Christie said, adding that Romney "is not someone who is deciding to run for president off the back of an envelope."
Christie's endorsement helps solidify the perception that Romney is both the frontrunner and the establishment choice in the seemingly settled field. Many Republicans were slow to rally around Romney, who is viewed skeptically by many in the GOP base because of his moderate positions on many issues in the past and his decision to sign a universal health care law as governor.
Throughout the year alternatives to Romney have risen, and, in many cases, fallen in the polls. First came Rep. Michele Bachmann, who has fallen to the back of the pack, and then Texas Gov. Rick Perry, who has seen a serious slide in his poll numbers in recent weeks. Most recent has been the Christie boomlet and the rise of former Godfather's Pizza CEO Herman Cain, who has passed Perry in many polls.
But few major GOP donors and establishment Republicans see Cain as a viable long-term candidate, and Perry's poor debate performance has soured many big donors on the Texas governor. The Wall Street money that had been pushing Christie into the race is now flowing to Romney, and it will be difficult for Perry to compete with him in the northeast, a crucial region for fundraising. He will instead need to focus even more narrowly on his established donor base in Texas.
Christie is a particularly valuable endorsement for Romney, and could be a valuable asset on the campaign trail. The New Jersey governor's no-nonsense style has made him a star in his party after less than two years in office, and he could help Romney win over voters who are skeptical of the governor. In introducing Christie, Romney called him a "forthright" "American hero" who "has the following of a lot of folks across this country."
Christie spent part of the event defending Romney against charges that the health care law Romney signed in Massachusetts is similar to the "Obamacare" health care law, calling such claims "intellectually dishonest." He said "we should not allow people for political purposes to try to be disingenuous about what Governor Romney did," which Christie described as the responsible course of action for Massachusetts. Christie suggested states, not the federal government, should decide about their health care policy.(The Democratic National Committee responded by noting the many similarities between the two laws, including the individual mandate.)
Christie suggested that many politicians, including Mr. Obama, run for president because they think they can win, not because they know they can do the best job. Romney, he said, has put the issue of running the country first.
"Mitt Romney says 'I hope I can win, I know I'm right,'" Christie said.
When he said he wasn't going to run for president last week, Christie said that if he endorses, he'll work hard for the candidate.
"You know, as I said before, I'm not a halfway kind of guy," he said. "If I feel like there's someone in the field who gives us the best chance to defeat the president, I'll endorse that person. I'll work hard for that person."
Christie's endorsement won't just be a one-off event -- he'll make appearances with Romney on the stump. "He's all in," one senior Romney aide told CBS News.
Christie said last week that he does not see himself as a vice presidential candidate.
saying "I don't think there's anybody in America who thinks my personality is best suited to being Number Two."
"Can you imagine?" Christie said of a candidate who would tap him for the vice presidential slot. "The guy would probably want to get a food taster."
Yet in a conference call with reporters after the announcement, Christie did not definitively rule out accepting a vice presidential offer, only saying that his first priority was his responsibilities to New Jersey.
Christie said he'll be pushing his financial backers toward Romney, pointing to Billionaire venture capitalist and Home Depot co-founder Ken Langone, a onetime Christie backer who has thrown his support behind Romney.
In response to the news, Perry Campaign Communications Director Ray Sullivan said Perry "has the utmost respect for Gov. Christie and looks forward to his help unseating President Obama next year."