First he has to get elected.
The 2012 GOP nominee for president announced Friday he is running for the Utah Senate seat being vacated by GOP Sen. Orrin Hatch.
Romney, 70, is among the best-known names in U.S. politics. He has been a successful businessman, governor of heavily Democratic Massachusetts, Olympics rescuer and, more recently, one of his party's fiercest critics of President Donald Trump.
Arizona Sen. John McCain, who often has taken on Trump, was quick to welcome Romney, his rival in the 2008 White House race.
In a tweet Friday shortly after Romney announced his Senate bid, McCain said Romney "has shown the country what it means to lead with honor, integrity and civility. The people of #Utah and the nation need his strong voice, resolve and service now more than ever."
Sen. Richard Shelby, R-Ala., said Romney would bring the prestige of his previous roles to the Senate.
"I think he will be a plus-plus in the Senate," Shelby said, calling Romney "a thoughtful man" and a leader who at 70 is senior enough to be an elder statesman.
Shelby, 83, has had his differences with Trump. He publicly opposed a GOP nominee backed by Trump in Alabama's closely watched Senate race last year, declaring before the election that "the state of Alabama deserves better" than Roy Moore, a former judge accused of sexual contact with teenage girls decades ago.
Romney has the stature to make similar declarations when - or if - they are needed, Shelby said. "I know the governor and I think he would support good ideas," Shelby said.
Romney, a heavy favorite to win the Senate seat, will step in "immediately" as a leader in the Senate, said Idaho Sen. Jim Risch, who got to know Romney when both served as governors and when he co-chaired Romney's presidential campaigns in Idaho.
"He has broad experience, he has the prestige. He'll jump right in," Risch said.
Those expectations are based largely on Romney's record, rather than recent accomplishments. Romney has not served in elected office in more than a decade and lost bids for president in 2008 and 2012.
Trump has seized on Romney's failed presidential bids, saying in 2016 that Romney "choked like a dog."
It's not clear how Romney will relate to the president as a candidate or as a senator, should he win. While he denounced Trump during the 2016 presidential campaign, Romney softened his stance after the election and put himself forward as a candidate for secretary of state before Trump looked elsewhere.
Since then, Romney has spoken up from afar. He called out Trump after a deadly white supremacist rally in Charlottesville, Virginia, last year, and lashed out again last month when Trump used an obscenity to describe African countries during a White House meeting on immigration.
"The poverty of an aspiring immigrant's nation of origin is as irrelevant as their race," Romney tweeted, adding that comments attributed to the president were inconsistent with "America's history and antithetical to American values."
Despite those criticisms, Democrats say Romney and Trump are not all that different.
"While Mitt Romney desperately wants to separate himself from the extremism of the current administration, the basic policies of Trump's GOP were his before they were Donald Trump's," said DNC spokesman Vedant Patel, citing the recently enacted GOP tax cuts and efforts to repeal former President Barack Obama's health care law.
Patel called Romney "another multimillionaire looking out for himself, his rich neighbors and the special interests."
If he does go after Trump, Romney will find himself among a dwindling breed in Congress. McCain, who is suffering from brain cancer, has not appeared in the Senate since before Christmas, while fellow Arizona Sen. Jeff Flake is retiring at the end of the year. Sen. Bob Corker, R-Tenn., also has had public disputes with Trump, but has not criticized Trump in months and is reportedly reconsidering plans to retire.
House Speaker Paul Ryan, Romney's 2012 running mate, said Romney's "unparalleled experience, conservative leadership and lifetime of service" will serve him and Utah well in the Senate.
Romney "has my unwavering support, and the people of Utah will be getting an accomplished and decent man when they make him their next senator," Ryan said.
Kirk Jowers, the former chairman and general counsel of Romney's leadership PACs, said Romney "will always be a straight shooter" and will support the president when he takes actions that are good for America.
"If President Trump says or does something that he finds offensive or divisive, unnecessarily divisive, then I think you will continue to hear Romney as the voice of reason and conscience in the Republican Party," Jowers said.
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