19 months before the 2012 presidential election, Donald Trump's poll numbers are higher than any other GOP candidate, declared or undeclared. Surely this must make him the Republican frontrunner, divorces and bankruptcies be damned? 

Not really. As Jon Stewart explains, lots of White House hopefuls have held leads at the point in the process only to see their candidacies fizzle out (Joe Lieberman) or never even begin (Mario Cuomo). And those were real politicians, with staffs and experience and messages that didn't make Glenn Beck 'uncomfortable.'