That gave the former Massachusetts governor more than his rivals combined. And while Santorum in particular challenges the mathematical projections, Romney is amassing delegates at a rate that puts him on track to clinch control of nomination before the convention next summer.
Romney, campaigning in Missouri, took exception to a television commercial airing in both Southern states and said Santorum "is at the desperate end of his campaign." The commercial was backed by a super PAC that supports the former senator, not by him.
Santorum's camp had earlier issued a memo that dismissed as fuzzy math Romney's claim that he is on track to amass a delegate majority. "Simply put, time is on our side," it said.
Gingrich's aides issued a rebuttal of their own with the polls still open in the primary states. It said the primaries were not yet half over, and the former House speaker "is well positioned to win the GOP nomination."
The large amount of television advertising was testimony to the importance the contenders and their allies attached to the primaries in both Alabama and Mississippi.
All three candidates as well as super PACs supporting each of them ran television commercials. As has been the case all year, Restore Our Future, which backs Romney, spent more than any of the others. The group put down $1.3 million for television ads in Alabama, another $900,000 in Mississippi and more for radio on Christian and other radio stations as well as thousands of pieces of mail designed to help the former Massachusetts governor.
It was only in recent days that Romney seemed to sense a chance in Alabama and Mississippi, and he responded by increasing his television ad expenditures and his plans for campaigning in the states.
Born in Michigan and a longtime resident of Massachusetts, he told one audience the two primaries were "a bit of an away game for him" and drew laughs from another when he said he hoped to go hunting with an Alabama friend "who can actually show me which end of the rifle to shoot."
He generally steered away from criticizing his Republican rivals and aimed his rhetoric instead at Obama, whose prospects in both states are as dim next fall as anywhere in the country.
Santorum campaigned against the president and Romney simultaneously as he sought the support of conservatives who have fueled his recent surge.
In Biloxi, Miss., on Monday, he ridiculed the science behind global warming. "The dangers of carbon dioxide? Tell that to a plant, how dangerous carbon dioxide is," he said.
Gingrich spent part of his time pushing back against suggestions — including from his own staff — that he might drop out if he didn't notch a pair of Southern victories. His only two wins so far came in the South Carolina primary on Jan 21, and last week, when he won his political home state of Georgia.
Initial polls showed the former House speaker in a strong position in both states, but he abruptly canceled a campaign trip to Kansas in advance of the state's caucuses late last week to remain in the South.
He used a recorded telephone message from Chuck Norris, the actor and Karate champion, for a last-minute appeal to voters in Alabama.
Associated Press writers Charles Babington in St. Louis and Beth Fouhy and Philip Elliott in Montgomery, Ala., contributed to this report.
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