WASHINGTON (AP) -- Mitt Romney has clinched the Republican nomination for president with a win in the Texas primary.
The Associated Press delegate count shows that Romney surpassed the 1,144 delegates needed to win the nomination during Tuesday's primary. Early returns show Romney posting a big win in Texas.
It's a triumph of endurance for a candidate who came up short four years ago and had to fight hard this year as voters flirted with a carousel of GOP rivals.
Romney reached the nomination milestone with a steady message of concern about the U.S. economy, a campaign organization that dwarfed those of his GOP opponents, and a fundraising operation second only to that of his Democratic opponent in the general election, President Barack Obama.
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Mitt Romney is set to clinch the Republican presidential nomination Tuesday night with a win in the Texas primary, a triumph of endurance for a candidate who came up short four years ago and had to fight hard this year as voters flirted with a carousel of GOP rivals.
According to the Associated Press count, Romney was sure to pass the 1,144 delegates needed to win the nomination on Tuesday unless he flopped badly in the Texas contest, an unlikely scenario with no one else campaigning.
The former Massachusetts governor has reached the nomination milestone with a steady message of concern about the U.S. economy, a campaign organization that dwarfed those of his GOP foes and a fundraising operation second only to that of his Democratic opponent in the general election, President Barack Obama.
"That goal is accomplished, but there's a much bigger goal to be accomplished and that's winning the presidency," said Rich Beeson, Romney's political director. "So while you can take a certain amount of satisfaction and pride for (Romney) and what he's accomplished, he's very resolved to say, `Our work isn't done.'"
Romney must now fire up conservatives who still doubt him while persuading swing voters that he can do a better job fixing the nation's struggling economy than Obama. In Obama, he will face a well-funded candidate with a proven campaign team in an election that will be heavily influenced by the economy.
"It's these economic indicators that will more or less trump any good or bad that Romney potentially got out of primary season," said Josh Putnam, an assistant political science professor at Davidson College who writes the political blog Frontloading HQ.
Romney opened his day in Colorado's coal country, where he spoke directly to small town America: "I'm not going to forget Craig, Colorado. I'm not going to forget communities like this across the country that are hurting right now under this president," he said. Local officials report that the area's economy is improving, but Romney said the recovery is too slow.
The Colorado event was the first stop in a Tuesday swing that ends at a Las Vegas fundraiser with Donald Trump, who has been renewing discredited suggestions that Obama wasn't born in the United States. The Obama campaign released a video Tuesday criticizing Romney's unwillingness to stand up to Trump and the more extreme elements in his party. Romney says he believes Obama was born in America but has yet to condemn Trump's repeated insinuations to the contrary.
"Mitt Romney's continued embrace of Donald Trump and refusal to condemn his disgraceful conspiracy theories demonstrates his complete lack of moral leadership," Obama's deputy campaign manager, Stephanie Cutter, said in a statement. "If Mitt Romney lacks the backbone to stand up to a charlatan like Donald Trump because he's so concerned about lining his campaign's pockets, what does that say about the kind of president he would be?"
Asked Monday about Trump's contentions, Romney said, "I don't agree with all the people who support me. And my guess is they don't all agree with everything I believe in." He added, "But I need to get 50.1 percent or more. And I'm appreciative to have the help of a lot of good people."
Republicans won't officially nominate Romney until late August at the GOP national convention in Tampa, Fla. He enters the Texas primary with 1,086 convention delegates - 58 shy of the 1,144 needed to win the nomination.
Texas has 152 delegates at stake and they are awarded in proportion to the statewide vote. That means Romney has to get at least 38 percent of the vote there to go over the top. In recent primaries in Kentucky, Arkansas, Nebraska and Oregon, he has done no worse than 67 percent.
Texas Republicans also will vote in a Senate primary to choose a candidate to run for the seat being vacated by Sen. Kay Bailey Hutchison. Lt. Gov. David Dewhurst is facing state Solicitor General Ted Cruz and Dallas Mayor Tom Leppert. If no one gets more than 50 percent of the vote, the top two finishers will go to a runoff in July. The nominee will be strongly favored to win in November in heavily Republican Texas.
Romney, 65, is clinching the presidential nomination later in the calendar than any recent Republican candidate - but not quite as late as Obama in 2008. Obama clinched the Democratic nomination on June 3, 2008, at the end of an epic primary battle with Hillary Rodham Clinton. Four years ago, John McCain reached the threshold on March 4, after Romney had dropped out of the race about a month earlier.
This year's primary fight was extended by a back-loaded primary calendar, new GOP rules that generally awarded fewer delegates for winning a state and a Republican electorate that built up several other candidates before settling on Romney.
Rick Perry, Herman Cain, Newt Gingrich, Rick Santorum and Trump - all of them sat atop the Republican field at some point. But Romney outlasted them all, even as some GOP voters and tea party backers questioned his conservative credentials.
The primary race started in January with Santorum, the former Pennsylvania senator, narrowly edging Romney in the Iowa caucuses. Romney rebounded with a big win in New Hampshire before Gingrich, the former House speaker, won South Carolina.
Romney responded with a barrage of negative ads against Gingrich in Florida and got a much-needed 14-point win. Romney's opponents fought back: Gingrich called him a liar, and Santorum said Romney was "the worst Republican in the country" to run against Obama.
Gingrich and Santorum assailed Romney's work at Bain Capital, the private equity firm he co-founded, saying the firm sometimes made millions at the expense of workers and jobs. It is a line of attack that Obama has promised to carry all the way to November.
On Feb. 7 Santorum swept all three contests in Missouri, Colorado and Minnesota, raising questions about Romney's status as the front-runner. After a 17-day break in the voting, Romney responded with wins in Arizona, Michigan and Washington state before essentially locking up the nomination on March 6, this year's version of Super Tuesday.
Romney has been in general-election mode for weeks, raising money and focusing on Obama, largely ignoring the primaries since his competitors dropped out or stopped campaigning. Santorum suspended his campaign April 10, and Gingrich left the race a few weeks later.
Both initially offered tepid endorsements of Romney, but on Sunday Gingrich gave a full-throated defense of Romney's campaign, saying on NBC's "Meet the Press" that he was "totally committed to Romney's election."
Texas Rep. Ron Paul said on May 14 he would no longer compete in primaries, though his supporters are still working to gain national delegates at state conventions.
Rich Galen, a Republican strategist who has been unaligned in the 2012 race, said the long, sometimes nasty primary fight should help Romney fine-tune his campaign organization so it can operate effectively in the general election. Galen doesn't, however, think it was relevant in toughening up Romney for the battle against Obama.
"Romney's been running for president for six years. He is as good a candidate as he's ever going to be," Galen said. "Whatever you say about him, he was better than everybody else in the race."
Associated Press writer Steve Peoples contributed to this report from Colorado.