Gingrich banks on wins in Alabama and Mississippi

Republican Newt Gingrich says he'll campaign for president until the party's nominating convention in August, but his candidacy largely rests on the results of Tuesday's primaries in Alabama and Mississippi.

The former House speaker is banking on a Southern strategy that so far has yielded victories only in South Carolina and Georgia, the latter a state he represented in Congress for 20 years. So winning Tuesday's contests is vital to sustaining his limping candidacy.

Gingrich was spending the day in Birmingham and planned to address a local Chamber of Commerce and hold a primary night event at a riverside hotel. A scheduled trip to the Birmingham Zoo was canceled due to weather.

Gingrich planned to be in Illinois on Wednesday to campaign for the March 20 primary there.

In Alabama and Mississippi, polling shows a tight three-way race among Gingrich, Mitt Romney and Rick Santorum.

In an address Monday to a Republican presidential forum in Birmingham, Gingrich implored voters to support him.

"I've stayed in this race for two reasons," he said. "I do not believe the two other candidates can beat President Obama. We have to win in a principled way with a big enough agenda and enough momentum to change Washington decisively."