Romney set to win Republican race
Mitt Romney is poised to clinch the Republican presidential nomination after Tuesday's Texas primary, a largely uncontested election which will formalise the former Massachusetts governor's status as President Barack Obama's general election challenger.
While Mr 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 presidential bid, and perhaps far earlier.
"It'll be a big day tomorrow," he told reporters on board his campaign plane on Monday evening. "I'm looking forward to the good news."
But his focus will be hundreds of miles north of Texas - he is scheduled to court voters and donors in Colorado and Nevada during a two-state swing punctuated by a Las Vegas fundraiser with celebrity real estate mogul Donald Trump.
The evening event comes amid fresh criticism from Republicans and Democrats over Mr Trump's continued questioning of Mr Obama's citizenship.
Mr Romney has not condemned Mr Trump's false claims, offering a fresh example of the presidential contender's reluctance to confront his party's more extreme elements.
There have been other examples in recent weeks that underscore Mr Romney's delicate push to win over sceptical conservatives while appealing to moderates and independents who generally deliver general election victories.
Asked to weigh in on Mr Trump's support for the so-called birther movement, Mr Romney declined to condemn the billionaire's latest suggestion that Mr Obama was born in Kenya: "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."
Polls suggest that the election between Mr Romney and Mr Obama will be very close, ultimately decided by several swing states, Colorado and Nevada among them.
The Texas primary offers 152 delegates; Romney is just 58 delegates shy of the 1,144 needed to become the nominee. His Republican rivals, Rick Santorum and Newt Gingrich, have already endorsed him, while libertarian-leaning Texas Representative Ron Paul has stopped actively campaigning.