Mitt Romney should clinch the Republican presidential nomination on Tuesday by winning the Texas primary, overcoming doubts about his ideological purity to become the party's 2012 flag bearer after a bruising battle.
Voters in the second most populous US state began casting ballots early Tuesday, with Romney the only Republican still actively campaigning for the nomination to challenge President Barack Obama in November.
An all-but-assured Texas victory will secure him the 1,144 delegates needed, capping a long, rough-and-tumble slog through dozens of state primaries and caucuses.
They also accused Romney of being the wrong candidate to challenge Obama on his historic health care reform, widely reviled by core conservatives, because as governor of Massachusetts he implemented similar reforms that the White House readily states formed the basis for the Obama plan.
But the pugnacious and well-funded Romney always bounced back, unleashing furious assaults on his challengers such as the one in Florida that helped him trounce former House speaker Gingrich, who had alarmed the Romney campaign by winning the South Carolina primary the week before.
In nominating a multimillionaire former businessman, the Republican Party is in familiar territory, but in one key respect Romney is making history, as the nation's first-ever Mormon nominee of a major political party.
The Republican base has long been dominated by evangelical Christians, and Romney's faith has occasionally emerged as a campaign topic, with some religious leaders expressing suspicion about his religion.
But Romney is counting on Americans seeing him as the pragmatic problem solver with the business credentials to turn the economy around better than Obama has.
"The last four years have been a disappointment for the American people," Romney told a crowd Tuesday in Craig, Colorado.
"Every recession ultimately comes to an end, but you'd expect this deep recession to come back to an aggressive turnaround, and it didn't happen. This president's policies made it harder for America to get on its feet again."
Romney, 65, pivoted toward Obama in his campaign speeches and events more than a month ago, when it became clear his long march toward the nomination at the party convention in August would not be stopped.
But in Craig he made no mention of passing the delegate threshold, and his plans for later in the day do not include the Lone Star State.
Instead he travels from Colorado to Las Vegas, Nevada, where he attends a fundraiser with Donald Trump, the legendary business tycoon who himself was considering a presidential run earlier this year but endorsed Romney in February.
Trump was in the spotlight Friday for again trumpeting his contentious "birther" conspiracy views in which he suspects Obama may have been born in Kenya, instead of Hawaii.
Romney says he does believe Obama was born in Hawaii but has caught flak for not repudiating the recent remarks by the man who will host him at a Trump property in Las Vegas.
"You know, 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," Romney said aboard his campaign plane on Monday.
"But I need to get 50.1 percent or more and I'm appreciative to have the help of a lot of good people."
The Obama re-election team quickly released a video hitting Romney for failing to distance himself from the birther issue.
Polls show a steadily tightening White House race, with Republicans coalescing behind Romney in the weeks since Gingrich and Santorum dropped out of the race.
Poll aggregates show Obama narrowly ahead. The latest average by website RealClearPolitics shows the president with a two-percent lead, 45.6 to 43.6 percent.
Source: AFP American Edition