Not to be a skunk at the garden party, but Michael Bloomberg's name must appear on a ballot before anyone could vote for him (a national write-in campaign ain't a-gonna happen). The Democrat-turned-Republican (he's a RINO, some say, Republican In Name Only) began his 2001 mayoralty run as a 40-point underdog. The primary date of September 11, 2001, had to be re-scheduled after voting had begun in the early hours. Having defeated a GOP primary challenger, Bloomberg - who was not well-known to the general public - used the print, TV and radio outlet resources of Bloomberg L.P. in an unprecedented multi-lingual media blitz that eventually saw him endorsed by every small non-English language newsletter in NYC. Bloomberg outspent his Democratic opponent 5-1, having put up $73 Million out of his own pocket. He secured the nomination of the controversial Independence Party (in NY, a candidate may run as the nominee of more than one party and the candidate's total votes are gathered under their major party label). Giuliani's endorsement gave him the decisive victory boost.
Were he to run nationally, he'd likely use H. Ross Perot's 1992 strategy of having local supporters petition state election commissions for ballot placement. Fair to say that Republican and Democratic state committees, mindful of Perot's and Nader's influences, will challenge his nomination papers tooth-and-nail. Bloomberg, unlike Perot in '92, has a full-time day job that limits his out-of-state appearances. When talk began percolating in late 2006 about his leaving the GOP and running as an independent Presidential candidate, billionaire Bloomberg reportedly indicated that he could spent $500 Million of his own money and not worry about it. Howard Wolfson, Hillary's media guru, at the time stated that Bloomberg would take votes away from the Democratic nominee and no one else.
While Bloomberg is a risk-taker, he is not a fool. The prospect of running without at least a realistic possibility of victory will likely stay the hand of the man from Allston, Brookline and Medford, MA.