The latest edition of TIME‘s “The Big Questions” features Mark Halperin‘s take on the most likely 2012 presidential matchup:

So are we headed for an Obama-Romney matchup?

There’s about a 75% chance that they’ll be the major-party nominees, but don’t fill out your scorecard just yet. Gingrich, Rick Perry and Jon Huntsman still have triple bank shots that could knock off Romney. And if anyone other than Romney wins the nomination, look for a major third-party or independent candidate. The newbie group Americans Elect will likely get a ballot slot for a candidate to be named in 2012. Amid one of the most volatile periods in modern U.S. political history, it’s way too soon to know where this is headed.