CRAIG, Colo. (AP) — Mitt Romney is poised to clinch the Republican presidential nomination after Tuesday's Texas GOP primary, a largely uncontested election that will formalize the former Massachusetts governor's status as President Barack Obama's general election challenger.

While Romney's nomination has been virtually assured for a month, the day marks the culmination of several years of work, dating back to his unsuccessful 2008 effort, and perhaps far earlier.

Romney told reporters he was "looking forward to the good news."

But Romney's focus Tuesday will be hundreds of miles north of Texas in Colorado and Nevada, where he's scheduled to court voters and donors during a two-state swing punctuated by a Las Vegas fundraiser with Donald Trump.

The fundraiser comes amid fresh criticism from Republicans and Democrats over Trump's continued questioning of Obama's citizenship.