Mitt Romney has clinched the Republican presidential nomination in the US to face Barack Obama in the November election.
On Tuesday night he mathematically secured it with a win in the Texas primary after months on the campaign trail to win over skeptical conservative voters.
In a statement, Romney said he was humbled to win enough of Texas' 155 delegates to secure the nomination.
"Our party has come together with the goal of putting the failures of the last three and a half years behind us. I have no illusions about the difficulties of the task before us. But whatever challenges lie ahead, we will settle for nothing less than getting America back on the path to full employment and prosperity," he said.
Though he has been the presumptive nominee for weeks since Rick Santorum and Newt Gingrich left the race, Republicans will not officially nominate Romney until the party's national convention in Tampa, Florida in late August.
He entered the Texas primary with 1,086 convention delegates - 58 shy of the 1,144 needed to win the nomination.
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.
It is always difficult to unseat an incumbent president and Romney is considered the underdog. But with the economy staggering along, polls are close.
All indications are that Americans face the possibility of a cliffhanger election in November that will be decided by relatively small percentages of voters in as many as a dozen battleground states, such as Ohio, Florida and Virginia.
The former Massachusetts governor now faces a lengthy to-do list to gird for his duel with Obama, from picking a vice presidential running mate to raising hundreds of millions of dollars for a national campaign.
In the immediate weeks ahead, his goal is to bolster his case that Obama has been ineffective in handling the sluggish US economy and hostile to job creators.