Two debate moments have defined the Republican presidential primary race so far. One sent a campaign into a slow death spiral, the other solidified a new entrant as the frontrunner.

The first moment came in June at the New Hampshire Republican debate when former Minnesota Gov. Tim Pawlenty failed to back up his “Obamneycare” charge with former Massachusetts Gov. Mitt Romney on stage with him. The exchange made Pawlenty look weak and his poll and fundraising numbers only fell after that point.