Mitt Romney could only savor his Michigan primary victory for so long before having to start all over again Wednesday with the rest of the GOP presidential candidate mix in South Carolina.

Having won his second state in the Republican race for the White House, the Michigan native, who has emerged as the delegate and raw vote front-runner, was scheduled for a busy day beginning in Bluffton, S.C., and continuing until Saturday's Republican primary.

Romney was beaming Tuesday night after winning the affection of home state poll-goers, pulling out an upset against rival John McCain by appealing to the Republican base with a strong economic and values message.

With 100 percent of the voting in, Romney earned 39 percent of the vote over McCain with 30 percent. Mike Huckabee had 16 percent while Ron Paul polled at 6 percent. Fred Thompson had 4 percent and Rudy Giuliani was at 3 percent.

"Tonight proves you can't tell an American there's something they just can't do because Americans can do whatever they set their hearts on, and tonight is a victory of optimism over Washington-style pessimism," Romney said to a raucous crowd of supporters in Southfield, Mich. "The lobbyists and the politicians realize that America now understands that Washington is broken and we're going to do something about it."

Democratic delegates are not being seated at the national convention and most of the party's candidates withdrew from the Michigan race, leaving Hillary Clinton, Dennis Kucinich and Mike Gravel the only active contenders on that ballot.

With 100 percent of precincts in, Clinton had won 55 percent compared to 40 percent for "uncommitted," 4 percent for Kucinich and less than 1 percent for Gravel.

The win put Romney in a strong position heading into Saturday's South Carolina primary, Florida's primary on Jan. 29 and Super Tuesday on Feb. 5.

"It's incredibly validating for the campaign," said a senior Romney campaign official, adding that Romney is content to let his opponents -- McCain, Thompson and Huckabee -- go at each other as they vie for the top spot in South Carolina.

"We've been in the middle of all the fights so far. We're going to let them fight for awhile. Second, third or even fourth is fine for us in South Carolina. We will be strong in Florida, regardless," the official said.

Romney spokesman Kevin Madden said Romney's message on the economy resonated with Michigan voters.

"We feel very good, very optimistic about the turnout we've had," he told FOX News, adding that the governor's message appealed to voters "who want to see somebody who can bring together economic conservatives, social conservatives and national conservatives, but also who's the leader for the future, who's going to bring the Republican Party back, who's going to help bring Michigan's economy back and the American economy back."

McCain called Romney after the race to wish him congratulations. He then addressed supporters in South Carolina, where he and Huckabee arrived Tuesday afternoon rather than facing their expected defeats in Michigan.

"For a minute there in New Hampshire, I thought this campaign might be getting easier, but you know what? We've gotten pretty good at doing things the hard way, and I think we've shown them, we don't mind a fight," McCain told supporters in Charleston.

But as if there weren't enough ill will between the two camps, McCain's concession speech was stepped on by Romney's delivery of his victory speech. The campaign's two managers apparently tried to choreograph the appearances, but the Romney camp mis-timed their candidate's arrival. McCain was coming out to make his speech as Romney's brother was making the introduction for his sibling. As the networks went to cover the Romney remarks, McCain was cut off, leaving his camp none too pleased with the outcome.

On a different note, Huckabee, who spoke to his backers before the two other candidates got tangled up in airtime, was upbeat despite his third place finish and noted that he was outspent 50 to 1 in Michigan.

"I congratulate Mitt Romney, he won a great race. He worked hard, of course he has a great base there ... So it looks like I won Iowa, John McCain won New Hampshire, Mitt Romney won Michigan, but ladies and gentleman, we're going to win South Carolina," he told supporters from Lexington, S.C.

"We put a flag in the ground here Saturday. We're going to make it real clear that the first in the South primary is going to give their support to the first in the South candidate, who understands that his nation needs leadership and leadership that comes right from the earth and right from the heart of the people," Huckabee continued.

According to an analysis of presidential advertising by the nonpartisan Michigan Campaign Finance Network, Romney put at least $20 million of his personal fortune into his bid, campaigned in the state more than his rivals and spent more than $2 million in TV ads in Michigan. McCain paid for more than $740,00 in ads and Huckabee spent more than $480,000.

Giuliani's campaign also issued a statement congratulating Romney.

"We congratulate Mitt Romney for wining his home state of Michigan. It’s clear after tonight that while the race remains fluid and competitive, our strategy remains on track. Rudy is going to continue to campaign aggressively in Florida and after the energy we’ve seen on the trail this past week, we’re confident that we’ll be successful on the 29th," said senior adviser Tony Carbonetti.

Giuliani did not compete in Michigan, and has been saving his big day for Florida. A RealClearPolitics average of polls in Florida showed a tie at the top with McCain and Giuliani at 21.3 percent, Huckabee at 18.3 percent and Romney at 17 percent.

In South Carolina, Huckabee leads with 26.5 percent compared to McCain with 22.8 percent, Romney at 16.8 percent and Thompson at 10.3 percent. Giuliani has 6.8 percent and Paul is at 5 percent in that spread.

Thompson offered congratulations to Romney, but tempered his effusiveness by saying Romney tailors his message to each audience, and that kind of positioning leaves him vulnerable. In fact, Thompson, who also didn't campaign in Michigan, said all the other candidates are flawed.

"I have drawn distinctions myself between not only Mitt Romney but John McCain," Thompson told FOX News. "But it's not a matter of who you're attacking, it's a matter of who's the one consistent conservative and has the record to back it up in this race, and you're talking to him."

Low turnout appeared to help Romney in Michigan's 2008 Republican presidential primary race, as the more committed party types braved frigid temperatures despite a night of snowfall that made traveling hazardous on Tuesday.

Only about 20 percent of eligible voters showed up at polling stations across the state, with about 12 percent of them voting in the GOP primary. All registered voters can participate in either party's primary.

Compared to the 2000 GOP Michigan primary when more than 1.3 million people voted, and nearly 550,000, or 41.5 percent, of those votes went to George W. Bush, only about 868,000 showed up to vote Tuesday, or 65.5 percent of the 2000 vote. Romney received nearly 338,000 of those votes.

According to FOX News exit polls, of those voting in the Republican primary, 25 percent were independents and 68 percent were Republicans. Of self-identified Republicans, 40 percent favored Romney compared to 25 percent for McCain.

The independents liked McCain, going for him 34 percent to 23 percent for Romney. Of that group, 20 percent support said they supported Paul and 15 percent chose Huckabee.

The biggest driver for Republicans to go to the poll was the economy. Slightly more than half -- 55 percent -- of those polled said the economy is the most important issue to them. Of those voters, 41 percent voted for Romney compared to 29 percent for McCain and 14 percent for Huckabee.

Romney also won conservatives, especially those who say they're "very conservative." Forty-five percent of those went for Romney compared to 25 percent to Huckabee. McCain came in third among this category here with 11 percent.

The news is not all bad for McCain. For one, it appears that Romney's attacks on McCain as a "Washington insider" incapable of bringing real change did not resonate with voters. While 30 percent said Romney is the candidate to bring about change, a close 28 percent favored McCain for that task.

As to the candidate's character, the most important aspect for 44 percent of Michigan GOP primary voters was whether the candidate "shares my values" while 28 percent prioritized someone who says what he believes and 21 percent thought experience was the most important quality in a candidate.

In that contest, values voters sided with Romney 30 percent to Huckabee's 27 percent, with 17 percent going for McCain and 10 percent for Paul.

As for those who made up their minds going into the voting booth, 39 percent said they voted for Romney while 25 percent went for McCain and 23 percent chose Huckabee.

FOX News' Carl Cameron, Megyn Kelly, Jake Gibson and Sharon Kehnemui Liss contributed to this report.