Mitt Romney isn't singing anymore.
A little more than two weeks after his off-key but enthusiastic renditions of "America the Beautiful" captured the spirit of a candidate who had won the Florida primary and seemed on the verge of locking down the Republican nomination for president, Romney is back in lackluster mode.
It's not just that Romney is facing a surprising challenge in his native state of Michigan from Rick Santorum, the former Pennsylvania senator who vaulted into contention in the state-by-state nomination battle with wins in Missouri, Minnesota and Colorado.
What alarms many Republican Party leaders and strategists are the signals they see from Romney's campaign as he struggles to support the notion that he is the inevitable nominee to face President Barack Obama in the November election.
They see the former Massachusetts governor as a candidate whose confidence appears shaken, and whose strategy and message now can seem off-key.
Gone are the vibrant rallies Romney held in Florida, replaced in Michigan by a series of low-energy round-table discussions.
This week, Romney often rushed through his stump speech as if he had a plane to catch, and made awkwardly curious remarks - "I love you" to a business group, and, "The trees are the right height" in Michigan - that made him seem particularly desperate for approval.
"I really count body language for a lot," said Republican strategist Rich Galen, adding with a joke that Romney, who ran for president in 2008, might have "hit the wall at the 5 1/2-year mark" of campaigning.
And then there were the two opinion pieces Romney wrote for newspapers - one in the Detroit News defending his opposition to the federal bailout of the auto industry, another in the Wall Street Journal in which he attacked Obama's policy on China as that nation's likely future leader, Xi Jinping, visited the United States.
The moves were aimed at attracting support from conservatives who oppose government bailouts and think that Democrat Obama has not been tough enough in his trade policy with China.
But Romney's column on the auto bailout raised questions even within the Republican Party about his strategy in Michigan, where his father was an auto executive and a governor - and where a loss in the February 28 primary could be devastating to his campaign.
Some strategists and party leaders wondered why Romney would continue to remind Michigan voters - millions of whom have ties to the auto industry - that he opposed the $81 billion bailout widely viewed as having saved the industry.
"I think his personal confidence is shaken," said political analyst Larry Sabato of the University of Virginia. "He thought it was all over after Florida.
"No matter what they say," Sabato said of Romney's campaign, a loss to Santorum in Michigan would be a "major psychological blow."
Sabato said that the longer the campaign goes on, the more Republican voters are reminded of the concerns they have had about Romney's ability to beat Obama.
"He's a gaffe machine, he can't seem to connect with regular voters, he can't seem to get out of tight spots," Sabato said. "The only thing holding him up is a very weak field" that includes Santorum, former U.S. House of Representatives Speaker Newt Gingrich and Texas congressman Ron Paul.
Santorum is attractive to socially conservative Republicans who hold significant sway in the nomination process because he is strictly anti-abortion and emphasizes his Catholic faith. In doing so, he has subtly reminded conservatives that Romney is a Mormon and that Gingrich is a converted Catholic who has been married three times.
For now, Romney's counter-attack seems focused on casting himself as a staunch conservative, a response to suspicions about his moderate stances on healthcare, abortion and other issues when he was Massachusetts governor.
Meanwhile, the independent "Super PAC" (political action committee) that supports Romney has bought a total of $7.7 million of air time in Michigan and several other states, presumably to launch a wave of TV ads casting Santorum as a Washington insider and big spender of taxpayers' money.
Romney senior adviser Eric Fehrnstrom says the campaign is proceeding according to plan, and that Romney -- who is in Salt Lake City this weekend to mark the 10th anniversary of the Winter Olympics he led -- is sticking to his message that he "is the best person to lead on jobs and the economy."
"It's steady as she goes," Fehrnstrom said. "We've seen opponents come and go, and through it all we have come out ahead."