When Republicans start attacking each other instead of, say, a black Democratic president, there's probably a reason.
Four names which are regularly bandied about for the 2012 presidential nomination are the wingnut-friendly Palin and Huckabee, and the would-be grownup "moderates" Romney and Gingrich.
Right now, Gingrich is attacking Romney's health care initiatives in Massachusetts. Which is exactly what he would do if he was thinking about competing with Romney for the rapidly-shrinking non-crazy electorate within the GOP.
Let's see if he also criticizes the other two -- particularly Palin.
**UPDATE** -- Newt is also out raising money for the Iowa Republican party. So, yeah, he's running.