Updated

Newt Gingrich could be facing a win-or-walk-away situation in the Deep South on Tuesday -- and the early numbers are not promising for the trailing presidential candidate, with two new polls showing him behind in Alabama.

The new polls each showed a different leader in the state, neither of them Gingrich. In an Alabama Education Association poll, Mitt Romney was ahead. A survey out of Alabama State University gave the lead to Rick Santorum.

Gingrich's campaign brushed off the results. But they underscore the challenge the former House speaker faces.

His entire campaign strategy rests on big wins in southern states -- the next of which, Alabama and Mississippi, vote Tuesday. Though Gingrich won big in his home state of Georgia on Super Tuesday, that strategy suffered a blow after he also lost Tennessee to Santorum. And if Gingrich loses either Mississippi or Alabama on Tuesday, or both, he could be left with an almost invisible path to the nomination.

"I think that ruins his Southern strategy," Republican strategist Brad Blakeman told FoxNews.com. "You can't claim to be a regional candidate and claim you have support in the South, and then not be able to win contests to evidence your belief."

More On This...

    Gingrich's rivals are competing hard for those Southern votes next Tuesday, as they try to nudge him out of the race.

    Romney planned a rally in Mississippi on Thursday as Gingrich campaigned there. Santorum was campaigning across Alabama.

    Meanwhile, Santorum's super PAC rolled out new ad buys in both states a day after publicly urging Gingrich to bow out. The ads question how Romney or Gingrich could beat President Obama in the fall considering their past support for an individual mandate -- the crux of the federal health care overhaul all GOP candidates are campaigning against.

    The Gingrich campaign acknowledges it needs to do well in the South.

    "Everything from Spartanburg all the way to Texas, they all need to go for Gingrich," spokesman R.C. Hammond said.

    But the campaign says it is devoting its resources to those states, canceling appearances in Kansas ahead of that state's caucuses to focus on Alabama and Mississippi.

    Hammond on Thursday downplayed the results of the latest Alabama polls.

    "We demonstrated in (Tennessee and Oklahoma) we can close 10-point gaps," he said -- though Gingrich still lost Tennessee and Oklahoma to Santorum. "Our $2.50 a gallon message is resonating. Look for the same scenario pushing across the finish line."

    Gingrich, at a stop in Birmingham Wednesday night, made the case for his continued candidacy.

    He argued that because Santorum lost his reelection fight for U.S. Senate in Pennsylvania in 2006 by a big margin, Democrats would just return to the same playbook they used to defeat him in 2012.

    "Despite the many requests by the Washington establishment, I am staying in this race," Gingrich said to cheers. "I'm prepared to take on Barack Obama, and I'm prepared to take on the establishment in both parties. And that does make me different."

    Santorum's backers have argued that Gingrich's presence in the race is preventing their candidate from picking up more of the conservative vote and waging a more competitive battle against Romney. Romney won six of the 10 Super Tuesday states, and continues to build his delegate lead over the field.

    Blakeman said Gingrich's path to the nomination is already very difficult. He said that unlike Ron Paul, who has won zero states but has shown no sign of quitting, Gingrich will probably not stay in the race just for the sake of playing an outsized role at the convention or influencing the party platform.

    For now, it is still technically possible for Gingrich to win. But he would need to win roughly 70 percent of the remaining delegates.

    The latest Associated Press delegate count shows Romney with 415, followed by Santorum with 176. Gingrich has 105, and Paul has 47. It takes 1,144 to win.

    Fox News' Joy Lin contributed to this report.