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SOUTHAVEN, Miss. -- Pick the wrong presidential candidate, Newt Gingrich cautioned Thursday, and the Republican Party might doom itself even if it wins back the White House.

"Frankly, just any old victory isn't good enough," he said during a rally in the fourth largest city in the state, just across the border from Memphis. "If all we get is somebody to preside over the decay, then frankly two years from now the Republican brand will be shattered."

Gingrich warned against a repeat of the 2006 mid-term elections, where Democrats swept both the House and the Senate because of dissatisfaction with President George W. Bush.

"It's useful to remember the only kind of Republican Party that can sustain a majority is a party dedicated to fundamentally changing Washington," the candidate told a crowd of over 200 people, drawing applause. "Part of where I am different from Governor Romney and Senator Santorum is my commitment to large positive solutions."

With his wife Callista at his side, the candidate stood on stage pledging to win a "victory so decisive that the country will have made a decision, and the country will communicate to the new Congress, the new House, the new Senate that the country wants real change in Washington, not just politics as usual."

Facing ever-increasing odds at locking up a competitive number of delegates as Romney prances ahead of the pack in the delegate count, Gingrich was making pit stops across the vast expanse of Mississippi one day after barnstorming Alabama. The latest polls indicate he's in third place in Alabama but there hasn't been any recent polling of the Mississippi Republican electorate.

"This is without any question the most important primary that Mississippi's had for the presidency," Gingrich said. "Mississippi matters in this particular cycle."

In an interview with Greta Van Susteren, Gingrich painted a path to the nomination where, in the absence of a candidate who sustains a "long winning streak," the Republican convention in Tampa would provide an opportunity for the party to have a "conversation about who could win."

"I think people generally agree I could debate Obama better than anybody else, and have a better chance in that sense, of defeating Obama," he said, pinning his hopes on a brokered convention.