ATLANTA — Voters will be making their picks across Georgia on Tuesday in what could be the biggest test yet for Newt Gingrich as he fights to keep his bid alive for the GOP presidential nomination.

Gingrich was favored to win in Georgia but his rivals spent time and resources in the state, hoping to grab a share of the state's 76 delegates and for a chance to deal Gingrich a humiliating defeat in the state he represented in Congress for 20 years. The polls were scheduled to be open from 7 a.m. until 7 p.m.

The former House Speaker didn't take any chances. He spent much of the week in the days leading up to Tuesday's contest campaigning in Georgia rather than logging time in the other nine states holding Super Tuesday contests. A loss in Georgia, Gingrich told voters at campaign stops, could cripple his White House hopes.

Mitt Romney and Rick Santorum didn't concede the state. Both campaigned in Atlanta's suburbs and sent surrogates to appeal to GOP groups across the state. But the two didn't have nearly as much riding on Georgia as Gingrich, who has pinned his presidential campaign on a strong showing in the state.

Not so long ago, the Gingrich camp viewed Georgia as a lock. But Santorum's trifecta of victories last month in Minnesota, Missouri and Colorado, and Romney's wins in Arizona and Michigan have extended Gingrich's losing streak and turned Georgia into a chance to prove he has staying power in the race.

A victory in Georgia on Tuesday and a strong showing in Tennessee, Oklahoma and Ohio could position him well for next week's contests in Mississippi and Alabama, two states with Republican voters similar to Georgia's. But a loss in the state that fostered his political rise could hurt his chances at becoming the party's presidential nominee.

Gingrich, who now lives in suburban Virginia, had a slew of advantages heading into the primary. He was backed by establishment support built on decades of relationships in Georgia, where many GOP figures still view him with an almost reverential vibe for his role in building up the party. He also had the endorsements of state Republican heavyweights, including Gov. Nathan Deal and former presidential candidate Herman Cain.

Gingrich also played up his local ties whenever given the chance. He made stops last week at the University of West Georgia, where he taught geography and history during the 1970s, and the Capitol, where supporters wore buttons identifying themselves as members of "Newt's Army." He also played to Georgia voters' concerns over rising fuel prices, vowing that his energy plan would reduce gas to $2.50 a gallon.

But Georgia was hardly a given. The state's population jumped more than 18 percent since Gingrich last held office in the late 1990s, a flood of residents who may have little memory of his time in government. Meanwhile, Santorum made a play for the social conservative vote across the state, and Romney's campaign hoped to build on a base of support that earned him 30 percent of the vote in the 2008 Republican presidential primary won by former Arkansas Gov. Mike Huckabee.

Other states holding Super Tuesday contests were Alaska, Idaho, Ohio, Oklahoma, Massachusetts, North Dakota, Tennessee, Vermont and Virginia.