Mitt Romney could be running out of time.

A crucial debate Wednesday night will be his last opportunity to speak to a national audience before next week's Michigan primary and next month's Super Tuesday voting.

The Republican race for president has completely flip-flopped since the last time Romney and Rick Santorum took to the stage.

ABC's Tahman Bradley has the details.

Rick Santorum will find out how it feels to be the front-runner.  After surging to the top of the Republican field, Santorum and his
conservative social and religious views will draw big attention at a GOP candidate debate in Arizona.

Rick Santorum said, "I went out and took on the tough issues: Medicare, Medicade and social security, welfare reform. I was the leader."  Santorum is already on the defensive about his record in congress.  Leading the attack is Mitt Romney.

Romney said, "I don't think Rick Santorum's track record is that of a fiscal conservative."  Romney and his supporters are spending millions, flooding airwaves with negative ads targeting Santorum.

Santorum's religious views have taken center stage in recent days, after he questioned president Obama's "theology." 

In this 2008 speech, Santorum suggested Satan was attacking America.  He said, "If you were Satan, who would you go after in this day and age?  There is no one other than the United States."

Romney will try to get his campaign back on course today in Arizona announcing the details of his tax plan.

The Arizona and Michigan primaries are in less than a week away.  The former Massachusetts governor is desperate to win Michigan, the state
where he was born, and has taken to targeting both Santorum and President Obama.

Romney said, "I'm glad to see Michigan is coming back. It is coming back. But it's with no thanks to this president; almost everything he's done has made it hard for the economy to reboot."

Polls show the races in Michigan and Arizona in a dead heat.  Michigan is being called a must-win state for Mitt Romney.