By Nick Carey
MYRTLE BEACH, South Carolina (Reuters) - Everybody was waiting for Jim DeMint. Mitt Romney had reason to hope the South Carolina senator would repeat his 2008 endorsement of his presidential bid.
DeMint is the hero of conservatives in South Carolina, so his backing might well have clinched the crucial state for Romney. Newt Gingrich, Rick Santorum and Ron Paul had just as much reason to hope DeMint might support them, and put him in the role of kingmaker in the Republican race for the White House.
At a convention of the conservative Tea Party movement in Myrtle Beach on Sunday, DeMint made clear, however, they could all stop holding their collective breath.
The Republican lawmaker, who had refused to endorse anyone, said he was definitely staying on the sidelines.
"We've got a presidential race coming up and we've got a lot of good candidates," he said.
"I know that probably folks in this room feel strongly about them in a lot of different ways, and that's why I'm not getting involved," he added to laughter from the audience.
The Tea Party - with its calls for reduced government spending and regulation - is the hottest movement within the Republican Party. It helped more than three dozen conservative candidates get elected to Congress in the 2010 elections, helping Republicans regain control of the House of Representatives.
But the Tea Party's impact on the presidential campaign has been relatively muted. There is no consensus Tea Party candidate, because the movement is split among conservatives Gingrich, Santorum and Paul. Republicans are selecting a candidate to challenge Democratic President Barack Obama in the November election.
It is also unclear whether the movement that helped elect candidates from conservative, mostly white congressional districts will have the same appeal in national elections, in which the electorate is more diverse.
So instead of picking a favorite for the White House race, DeMint has a different strategy: to strengthen the Tea Party in the Senate and forge a bastion of fiscal conservatism against whoever wins the presidency.
"We need not only to take a majority in the Senate," DeMint told the convention. "We need a conservative majority in the Senate."
The idea, he said, was to have enough conservative Republicans in the chamber to keep the occupant of the White House, "whoever it is," in check. Democrats hold a 53-47 majority in the Senate, but many of their seats are up for grabs in the November elections.
The key to DeMint's Senate plan is a fundraising group, the Senate Conservatives Fund, which says it has so far raised $3.5 million for the 2012 campaign cycle. It has endorsed four Senate candidates in Texas, Ohio, Nebraska and Wisconsin.
In DeMint's newly published book, "Now or Never: Saving America From Economic Collapse," the senator lists the questions that the Senate Conservatives Fund asks candidates before backing them, including "Will you oppose all net tax increases?"
"Ultimately, Jim wants to see 10 to 15 conservative senators who won't change their minds on core issues," said David Woodard, a politics professor at Clemson University, who has known DeMint for 20 years and co-authored "Why We Whisper" with the senator, a book published in 2007.
"That's the way he sees his role."
DeMint has come under pressure to give a nod to a conservative presidential candidate who can stop Romney, a moderate former Massachusetts governor who is the front-runner ahead of Saturday's Republican primary in South Carolina.
The vote is seen by many as a last chance for former House Speaker Gingrich, former Pennsylvania Senator Santorum and Texas Governor Rick Perry to prove they can compete against Romney.
DeMint endorsed Romney in his failed presidential bid in 2008, before the Tea Party movement took off.
Friends, academics, Republican strategists and even opponents in South Carolina say DeMint will not go back on his word to stay on the sidelines.
"I have to say that while I disagree with Jim on many things, I have to admire his consistency and his commitment to his philosophy," said South Carolina Democratic Party Chairman Dick Harpootlian. "If DeMint endorsed Romney, he'd be the Republican nominee tomorrow."
"But as he has said he won't endorse anyone, I don't believe he will," Harpootlian added.
THE DEMINT DOCTRINE
DeMint has a record of going against the Republican Party establishment in the Senate.
Almost since he was first elected to the Senate in 2004, he has fought against party leadership over government spending and taxation, issues crucial to Tea Party insurgents bent on pulling the Republican Party further to the right.
"Jim was Tea Party before there was a Tea Party," Harpootlian said.
DeMint bucked the party line in 2010 by backing conservative Senate candidates like Marco Rubio in Florida against those favored by party leadership.
This year, his mission to add more conservatives is aimed at cutting spending, getting tough on illegal immigration, and repealing Obama's healthcare overhaul that requires people to buy health insurance by 2014 or face tax penalties.
Call it the DeMint doctrine.
He ruled out compromising with Democrats in Congress at a speech to the Tea Party convention on Saturday.
"The Democratic Party today is the party of those dependent on government who want more government. That's why we can't compromise with them, we have to beat them," DeMint said.
His rhetoric went down well at the 2010 elections but many voters are now fed up with gridlock in Congress, a sentiment that Obama is playing on as part of his re-election bid.
"If people like Jim DeMint refuse to back down and try to find a way to compromise with the other side, we end up with gridlock, which is what we've seen over the past year," said Danielle Vinson, professor of politics at Furman University in South Carolina.
"The policy of no compromise runs the risk of turning the Republicans into the minority party if the rest of the country doesn't find his (DeMint's) arguments compelling," she said.
Born in Greenville, South Carolina, in 1951, DeMint's parents divorced when he was a child. He was raised by his mother and in his book "Saving Freedom" he describes a hard upbringing.
After college, he worked in market research before setting up his own public relations firm The DeMint Group.
Jim Guth, a politics professor at Furman University, said DeMint's experience as a business owner heavily influenced his political career.
"He really sees issues of spending and taxes from the perspective of a small business owner," he said. "It's important to understand that background."
"DeMint has little sympathy for big corporations," Guth added. "He supports lower taxes, but he would equalize taxes across the board and close loopholes for corporations."
DeMint was elected to the House of Representatives in 1998 but unlike his predecessors who backed the textile industry in his district, DeMint spoke out in favor of free trade. Later in the Senate, he made a point of speaking out against the use of "earmarks" - used by lawmakers to bring federal funding home for pet projects.
In 2010, DeMint resisted calls for a congressional earmark to renovate the Port of Charleston so it could handle large cargo ships.
"There have been some frustrations in the business community about DeMint's ideological fervor and his refusal to bring home the bacon to South Carolina," said Chip Felkel, a Republican consultant in the state. "He took some flak for it, but that's just who he is. When he says something, he means it."
"Unlike some people, this is a deep personal calling for him and his consistency has made him hugely popular with Republican voters in South Carolina," he added.
(Editing by Alistair Bell, Eric Beech and Peter Cooney)