WASHINGTON - Mitt Romney clinched the Republican presidential nomination Tuesday with a win in the Texas primary, a triumph of endurance for a candidate who fought hard to win over skeptical conservative voters he must now fire up for the campaign against President Barack Obama.
According to the Associated Press count, Romney surpassed the 1,144 delegates needed to win the nomination by winning at least 97 delegates in the Texas primary.
Romney, who came up short in the Republican presidential race four years ago, outlasted a carousel of Republican rivals who dropped out of the state-by-state primary contest. None of his former rivals actively campaigned in Texas.
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 Republican foes and a fundraising operation second only to that of Obama, his Democratic opponent in the general election.
Romney would be the first Mormon to be nominated for president by a major party. His religion has been less of an issue than it was during his failed bid four years ago.
Romney must now energize conservatives who still doubt him, while persuading undecided voters that he can do a better job fixing the nation's struggling economy than Obama.
"We did it!" Romney proclaimed in a message to supporters, noting that "it's only the beginning."
"An honour and a privilege and a great responsibility," Romney told supporters at a fundraiser in Las Vegas. "And I know the road to 1,144 was long and hard, but I also know that the road to 11-06 — Nov. 6th — is also going to be long and it's going to be hard and it's going to be worth it because we're going to take back the White House and get America right again."
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.
Romney's campaign went on the attack over the economy Tuesday, releasing a Web video citing the Obama administration's loan-guarantee investments in four renewable-energy firms that lost money and laid off workers.
The message — "President Obama is fundamentally hostile to job creators" — has been a theme of the Romney campaign since he launched his presidential bid.
"We need to have presidents who understand how this economy works," Romney told reporters Tuesday. "Sometimes I just don't think he understands what it takes to help people. I know he wants to help, but he doesn't know what he's got to do."
Romney's message and his big day, however, were somewhat overshadowed by celebrity real estate mogul Donald Trump and his discredited suggestions that Obama wasn't born in the United States.
Romney spent Tuesday evening at a Las Vegas fundraiser with Trump, who had toyed with the idea of running for president. Romney says he believes Obama was born in America but has yet to condemn Trump's repeated insinuations to the contrary.
The Obama campaign released a video Tuesday criticizing Romney's unwillingness to stand up to Trump and the more extreme elements in his party.
"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?" Obama's deputy campaign manager, Stephanie Cutter, said in a statement.
Both Trump and Romney steered clear of the issue at Tuesday's fundraiser. 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 per cent 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 Republican National Convention in Tampa, Florida. Romney has 1,183 convention delegates.
He won at least 97 delegates in Texas with 33 left to be decided. The 152 delegates in Texas are awarded in proportion to the statewide vote. The other delegates were sprinkled among several candidates.
Texas Republicans also voted in a Senate primary to choose a candidate to run for the seat being vacated by Republican Sen. Kay Bailey Hutchison. The party establishment choice, Lt. Gov. David Dewhurst, and state Solicitor General Ted Cruz, supported by the small government, anti-tax tea party movement, were headed to a runoff in July.
With about three-fourths of precincts reporting, Dewhurst led with 45 per cent of the vote compared to 33 per cent for Cruz. Dewhurst, however, fell short of the majority he needed to avoid a runoff. The nominee will be strongly favoured 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.
Several other Republican contenders — including Newt Gingrich, a former speaker of the U.S. House of Representatives, and Rick Santorum, former U.S. Senator from Pennsylvania — earlier dropped out of the race as Romney's well-financed campaign gained momentum.
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.
Libertarian-leaning 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.
Associated Press writers Steve Peoples in Las Vegas and Stephen Ohlemacher in Washington contributed to this report.