(CNN) -- Wednesday night's CNN debate lands at a critical moment in the Republican race. This season, each debate has set the tone for the primary to follow. Newt Gingrich's savaging of the media helped propel him to victory in South Carolina. Mitt Romney's savaging of Gingrich helped him to clinch Florida. The current uncertainty about the race, and the extraordinary elasticity in the polls, is partly due to the fact that we haven't had a debate for a whole month. It's important, then, for each of the candidates to make a powerful impression in this last confrontation before Arizona and Michigan vote on February 28. Rick Santorum and Newt Gingrich will compete over who is the most conservative, and Ron Paul will push his unique brand of libertarianism. Same old, same old. But we might see something new from Mitt Romney: a glimmer of humanity.Timothy Stanley: The Wednesday evening presidential debate comes at a critical timeHe says Santorum is threatening to displace Romney as the front-runner in the raceHe says while Santorum is liked by GOP voters, many of them have doubts about RomneyStanley: Look for Romney to try to adopt a folksy, populist tone
But if _'s reinvention as a human being does pay off, it will be because Republicans desperately want it to work.