The latest news on what Newt Gingrich is correctly calling a roller-coaster ride: Mitt Romney is now leading in Michigan, according to one poll.Real Clear Politics says Romney's leading Santorum by 2 points in a new Mitchell/Rosetta Stone poll. Santorum's still slightly ahead in Michigan in the RCP poll average, but the gap between him and Romney has been narrowing in the past few days.The Michigan primary is next Tuesday.Among other campaign-circus stuff found this morning during my surfing:Politico's "Mitt's Burn Rate a Boon for Obama.""Mitt Romney is burning through cash�more than twice as fast as he's raising it, new...