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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