Charles Dharapak, Associated Press
Republican presidential candidates, from left, former Pennsylvania Sen. Rick Santorum, former Massachusetts Gov. Mitt Romney and former House Speaker Newt Gingrich pose for a photo at the start of the South Carolina Republican presidential candidate debate in Myrtle Beach, S.C., Monday, Jan. 16, 2012.

With Oklahoma safely in Rick Santorum's camp and Newt Gingrich holding a deathgrip on Georgia, the GOP action next Tuesday — Super Tuesday — appears to be shifting to Ohio, campaign watchers are saying after Mitt Romney's twin wins last night.

"Ohio has the largest delegate haul next week, and it also consists of the kind of blue-collar, Rust Belt voters that Republicans need to draw to win in November," notes Ed Morrissey at Hot Air. Ohio is, in fact, a do or die for Santorum, given that he has now branded himself as the gritty populist.

Looking forward, Ed Rogers at the Washington Post has a quick take away for both leaders. For Santorum, it's that "extremism on social issues gives you a ceiling." For Romney, it's "all the lessons he should have already learned, especially that he has be honest with himself about his failure to thrive and then reassess his message. Something makes him off-key too often and limits his emotional connection with voters. Santorum could have beat him."

"If Michigan proves to be a watershed in the GOP nominating fight — and it might — Mitt Romney should thank Catholics, women and suburban voters in the eastern part of the state," notes Paul Gigot at the Wall Street Journal. "They helped to give the native son his narrow victory over Rick Santorum, whose focus on social issues in the final days looks to have narrowed his coalition by enough to cost him a victory that could have propelled him to the nomination."

Romney remains the strongest GOP option, and the only one who has proved he can play nationally, writes Real Clear Politics' Carl Cannon. "On the plus side for the frontrunner, it has become clear that Ron Paul and Newt Gingrich lack the deep pockets and broad-based appeal for a truly national campaign effort. Gingrich, who has confidently predicted Romney’s demise for the better part of two months, is now reduced to angling for a Super Tuesday win in Georgia, the site of his old congressional district, but a place he never ran in statewide."

Unlike Michigan, which ran an open primary allowing voters to freely vote in either party's race, Ohio is a semi-open primary. That means a voter can switch parties temporarily at the voting booth by filling out a form. This will likely lower the allure of the crossover strategy.

As expected, Mitt Romney struck back hard Wednesday at Rick Santorum's direct appeal to Democrats in Michigan with a simple Youtube ad using CNN footage to highlight the cynical reasons Democrats got out for Santorum.

"It's a major issue. (Santorum is) trying to pass himself off as the true conservative in the race, but he's supporting the liberal Democrat line against Gov. Romney," said Romney spokesman Ryan Williams, according to McKay Coppins at Buzz Feed.

Meanwhile the temporarily forgotten but still undead Newt Gingrich looks to lock down his home state of Georgia as a path to relevance. "That is the key building block that we have to have to move forward in the presidential campaign. Georgia really does matter," said Gingrich, according to the Associated Press.

Eric Schulzke writes on national politics for the Deseret News. He can be contacted at [email protected].