By Deborah Charles
BIRMINGHAM, Alabama (Reuters) - Newt Gingrich may not be ready to admit it, but his presidential hopes are all but over and calls will be getting louder for him to step aside.
The former speaker of the U.S. House of Representatives, who had hoped to revitalize his sagging campaign for the Republican presidential nomination with wins in the South, came in a disappointing second in Mississippi and Alabama on Tuesday despite pouring money and time into the two states.
"This really was his last chance to show whether he had the ability to win," said Natalie Davis, professor of political science at Birmingham Southern College in Birmingham, Alabama. "If he can't win in Alabama ... he really can't win anywhere. This was his last stand and he lost."
Republican strategist Ford O'Connell predicted a chorus of politicians urging Gingrich to drop his White House bid.
"There absolutely will be calls for Gingrich to step aside," said O'Connell.
In a speech to a group of about 100 supporters in Birmingham shortly after Rick Santorum was projected winner in both Mississippi and Alabama, Gingrich said he would keep campaigning all the way to the Republican National Convention in Tampa, Florida, in August.
In the state-by-state race for the Republican nomination to face President Barack Obama in the November 6 election, Gingrich has won only two contests: South Carolina and his home state of Georgia, where he was a U.S. congressman for two decades.
He has been vying with Santorum to become the conservative alternative to the more liberal front-runner Mitt Romney.
Matt Towery, a former Gingrich adviser and political commentator, said he did not expect Gingrich to make any quick decisions whether he would pull out.
But Towery, who has known Gingrich for 32 years and said he does not act precipitously, said the campaign had to be considering it.
"The Gingrich campaign has to consider several things including financial resources going forward, upcoming states not necessarily favorable to him and calls from many - not necessarily in Romney or Santorum camps - that he should leave the race," said Towery.
"I do not expect Newt to make any decision on an immediate basis," he added.
Gingrich spokesman R.C. Hammond pulled back from his comment last week that Gingrich had to win Mississippi and Alabama in order to stay viable as a candidate.
"Whoever said that should be flogged," he said as it became clear that Gingrich would not win either state.
"We're going on. We're going to Tampa. No matter what happens," he said.
Gingrich refused to quit in a speech on Tuesday night after the results.
"I'd also point out that because this is proportional representation we're going to leave Alabama and Mississippi with a substantial number of delegates."
He may have been signaling an interest in being some sort of power broker at the convention.
"It sounded more like he thought a number of delegates gives him some bargaining power," said Davis. "Beyond that, I think he becomes irrelevant."
But even if Gingrich was hoping to become a king-maker of sorts at the Republican convention if no other candidate managed to win enough delegates to lock in the nomination, it would not be an easy road ahead.
Though outside fundraising and lobbying groups not officially linked to the campaign, known as super PACs, can advertise for Gingrich, they are not allowed to pay any money directly to the campaign and therefore cannot pay regular campaign expenses. So Gingrich would still need to keep raising money to keep the campaign running.
"It makes it very hard as an argument for donors to say I'm getting delegates just to block someone," said O'Connell. "The question is how much do Gingrich's backers not want to see Santorum win? Gingrich's presence in the race certainly hinders Rick Santorum, which benefits Mitt Romney."
(Editing by Alistair Bell and Mohammad Zargham)