Republican presidential hopefuls are today battling for the crucial Super Tuesday primary and caucus votes in 10 US states.
Mitt Romney is the front-runner to become the party’s nominee to face US president Barack Obama in the presidential poll in November.
His progress will depend largely on the vote in the bellwether state of Ohio, where polls show the former Massachusetts governor and Rick Santorum, a former Pennsylvania senator, in a virtual tie.
Mr Romney, who beat Mr Santorum in a close contest in Michigan last week, hopes to continue his winning trend, having won four consecutive contests including Saturday’s Washington state caucuses.
At stake in the 10 states that cast ballots on Super Tuesday are 419 delegates to the party’s August national convention, by far the most of any day in the primary season. A candidate must amass at least 1,144 to win the nomination.
The states going to the polls are Georgia, Idaho, Massachusetts, North Dakota, Ohio, Oklahoma, Tennessee, Vermont and Virginia, along with Alaska’s two-week-long caucuses.
Going into today’s balloting, Mr Romney leads with 203 delegates from previous contests, Mr Santorum has 92, Newt Gingrich has 33 and Ron Paul has 25.
Mr Romney, despite his lead, faces persistent scepticism among conservative voters who dislike his past moderate record.
The candidates competed to be the most hawkish on Iran and favorable to Israel before the powerful pro-Israel lobby group AIPAC today, telling Iran it would be in real danger if it goes nuclear while they are in the White House.
"If Iran doesn't get rid of nuclear facilities, we will tear them down ourselves," said Rick Santorum, the conservative former senator whose views on the subject already were well known. In January, Mr Santorum said he would be in favor of launching US air strikes against Iran's nuclear facilities.
He took the time to appear in person while Mr Romney and Mr Gingrich provided video remarks to the annual gathering in Washington of AIPAC, which includes some of Israel's staunchest supporters in the United States. Ron Paul, a libertarian who is critical of US support for Israel, did not participate.
Mr Romney, in a speech delivered by satellite link, assured AIPAC that if he becomes president, Israel will know that America stands at its side "in all conditions."
But Mr Romney was slightly more circumspect than Santorum in his choice of words about how he would respond as president to an Iranian nuclear program.
Mr Romney said he would end Mr Obama's "procrastination" on the matter by imposing further crippling sanctions on Tehran, and "I will make sure Iran knows of the very real peril that awaits if it becomes nuclear. As president, I will be ready to engage in diplomacy. But I will be just as ready to engage our military might," he said.
Mr Obama, meanwhile, is seeing his poll numbers rise in tandem with signs that the struggling US economy may finally be on a course towards sustained recovery.
He has also been helped considerably by the Republicans having been driven off their economic message by a detour into a nasty debate over whether religious-affiliated institutions such as hospitals and universities should be required to offer health insurance coverage for contraceptives.
The issue seems certain to deepen the concerns of many women voters who - along with the broad spectrum of all independents - are likely to determine the ultimate outcome in the November election. Polls show women are already turning back to Mr Obama.
The president picked today to hold his first news conference of the year, a chance to steal a bit of thunder from the Republicans and defend a record of economic stewardship that is under daily assault in the Republican campaign.
In the Republican race, a Romney loss in Ohio almost certainly would assure that the primary contest continues further into March or perhaps beyond.
The focus on social issues has propelled the success of Mr Santorum, who campaigns as a social conservative and is the latest candidate to pose a threat to Mr Romney.
Having fallen behind Mr Santorum in Ohio last month, Mr Romney has closed the gap in recent days. It is a familiar trend for Mr Romney, whose superior fundraising and turnout operation helped him turn deficits in Florida and Michigan into victories.
Third-placed Newt Gingrich, the former speaker of the House of Representatives, has focused his efforts on Georgia, the state that he represented in Congress for two decades. Georgia is part of Mr Gingrich’s strategy to reinvigorate his once top-tier candidacy by sweeping primaries in the American south.
Mr Paul, who holds a small but loyal bloc of voters who favour his small-government, low-tax libertarian message, has focused on the smaller states that vote at caucus meetings which are easier to win for a low budget candidacy like his.
AP