After months on the sidelines, Rick Santorum finally gets his chance at centre stage in a debate of Republican US presidential candidates today, as well as the increased scrutiny that comes with it.
Mr Santorum, surging in opinion polls, is likely to face tough questions over his strong conservative views on social issues when he and rivals Mitt Romney, Newt Gingrich and Ron Paul gather for the CNN debate, which takes place at 1am GMT.
With the March 6th "Super Tuesday" nominating contests in 10 states approaching, this may be the last major opportunity for all the candidates to make their case before a national audience on why they should be the Republicans' choice to face Democratic president Barack Obama in the November 6th election.
Former Massachusetts governor Mr Romney, suddenly finding himself chasing Mr Santorum after running as the seemingly inevitable nominee, needs a breakthrough performance to halt the former Pennsylvania senator's surge and restore lustre to his own campaign.
Mr Romney proposed an overhaul of the US tax system today that would cut Americans' tax rates by 20 per cent and limit deductions for the wealthy.
Mr Santorum needs to build on his momentum going into the Arizona and Michigan primaries on February 28th and pave the way for Super Tuesday.
"For Santorum, there are a lot of expectations," said Republican strategist Ron Bonjean. "Now that he has reached the superstar status, he has to perform very well. Any stumble by Santorum will be magnified because of his front-runner status. He's going to have to face these attacks head-on."
Mr Santorum and Mr Romney are in a close race in Michigan, according to opinion polls, with most recent surveys showing the two divided by 4 percentage points or fewer.
An NBC/Marist poll on Wednesday had Romney at 37 per cent to Santorum at 35 per cent among likely primary voters in Michigan, a statistical dead heat.
The NBC/Marist poll gave Romney a lead of 42 per cent to 27 per cent over Santorum in Arizona. A Time/CNN poll on Tuesday found Romney ahead by 36 per cent to 32 per cent there.
Former private equity executive Mr Romney is likely to attack Mr Santorum over backing spending bills during his years in the Senate until he was voted out in 2006.
Mr Santorum was on the defensive in Arizona today about his time in Congress.
"We went there and we exposed scandal after scandal - bipartisan scandal, bipartisan scandals where Republicans and Democrats were doing things to undermine the credibility of Washington, D.C.," he said.
Mr Gingrich, himself a former front-runner who has a strong record in debates, has dropped in polls since Mr Romney surprisingly got the better of him in two televised encounters in Florida last month.
The race to find a Republican presidential nominee has been the most chaotic in decades as many conservatives have sought to find someone other than Mr Romney, who made his name in politics in heavily Democratic Massachusetts, as their candidate.
Mr Gingrich, Rick Perry, Herman Cain and Michele Bachmann all had their time in the limelight as alternatives to Romney, only to tumble away. Twenty previous debates have been crucial in determining who stays on top and who drops.
Reuters