KINGSPORT, Tenn. -- Republican Newt Gingrich launched a final, two-day swing across the South on Monday in advance of the biggest voting day so far of the year. Gingrich planned to campaign on Monday and Super Tuesday in Tennessee, Alabama and Georgia -- and vowed to exceed expectations in all the Southern states voting this week and next.

(Evan Vucci/AP)

Gingrich touted new polls showing that he is closing the gap in Tennessee, and he predicted again that he will win his home state of Georgia with ease. In a morning interview on CNN, Gingrich admitted that losing Georgia could end his campaign and acknowledged for the first time that winning Georgia and losing all the other states Tuesday "puts me in a more difficult position."

“But, on the other hand, next week we have Mississippi and Alabama and Kansas, and I think I'll win at least two out of three," Gingrich said in the interview. "The latest poll in Tennessee shows a 17-point jump, shows me very competitive in Tennessee."

A centerpiece of Gingrich's latest effort to regain momentum is a promise to bring the price of gasoline below $2.50 a gallon. He mentions the subject wherever he speaks, and it is the subject of a new TV ad the campaign is airing in Tennessee, Alabama and Mississippi.

An independent group supporting Gingrich is also advertising on TV and radio in those states and several others. Gingrich's hope is to overcome Santorum's lead among conservative voters while Santorum and Romney duke it out in the marquee state of Super Tuesday, Ohio.

Gingrich's rapid slide over the past six weeks from being the leading alternative to Mitt Romney -- a berth now held by Rick Santorum -- to back-of-the-pack obscurity has dramatically lowered his campaign’s expectations. A month ago, Gingrich promised to win Tennessee, Georgia and Oklahoma -- all the Southern states voting on Super Tuesday -- and to be competitive in Ohio.Now, Gingrich promises only to win Georgia, raising doubts about whether and how he can continue his run after Tuesday.

Nonetheless, Gingrich’s optimism has rebounded over the past 24 hours.

“The fact is, we'll be today in the Tri-Cities and then down in Knoxville and in Chattanooga," Gingrich said Monday on CNN. "J.C. Watts and Herman Cain and my daughter Jackie are all three campaigning in Oklahoma today. And I think we'll be very competitive in both of those states. And our hope is to also pick up some delegates in Ohio and possibly some in Idaho.

“Tuesday is going to be a mixed bag,” he added “and I think the race will go on. There won't be any decisive winner Tuesday.”

Whatever happens Tuesday, Gingrich says he’ll keep marching toward Tampa, where the Republican National Convention will take place in August. And he pledges an aggressive fight in the South, with a quick hop to Huntsville planned on Tuesday, a week before Alabama Republicans hit the polls. On Wednesday, Gingrich plans to return to Alabama for a full day of campaigning, then spend a day Mississippi and two days in Kansas, both of which also vote March 13.