Elections today: Incumbents such as New York's Mayor Bloomberg have spent big to ensure they keep their seats on Election Day.
Incumbent mayors are facing tougher-than-usual reelection bids due, in part, to a struggling national economy.
New York Mayor Michael Bloomberg has spent more on his own campaigns than any other politician in US history.
Polls suggest Michael Bloomberg has a 10 percentage point lead in the campaign for New York mayor. So why is he ramping up a blitz of attack ads?