On the flip side, removing Barbour from the equation gives some of the newer political faces, such as former Minnesota Gov. Tim Pawlenty and Ambassador to China Jon Huntsman, a new opening to compete for support from Barbour-friendly insiders who are uneasy about Romney…

Barbour’s withdrawal also alters the geography of the GOP primary: The Mississippian was seen as a formidable contender in South Carolina’s crucial primary. Since there’s no longer a strong and distinctively Southern candidate in the race, the whole region is a political question mark…

For Republicans accustomed to orderly primary campaigns, the idea of a tumultuous competition for Barbour’s establishment support is unsettling. And it raises the prospect that, for the first time in decades, the outcome of the Republican nomination fight might not have much to do with what influential conservative columnist Robert Novak called the “corporate party.”