WASHINGTON – Mitt Romney has clinched the Republican presidential nomination 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 Republican 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 Republican opponents, and a fundraising operation second only to that of his Democratic opponent in the general election, President Barack Obama.