That prospect was unthinkable for much of the campaign, as most polls had Thompson trailing Bloomberg by double digits. The mayor, an independent running on the Republican line, outspent his rival by a 14 to one spending margin, according to the New York Times. Preliminary figures suggest the cost of each vote ended up being about $157 for Bloomberg, and only $13 for Thompson.
"A lot of Democratic donors who sat on their wallets are kicking themselves tonight," Rep. Anthony Weiner, D-Brooklyn, tells the New York Daily News. The clear implication: Had those donors not opted-out of the race based on the belief that it was unwinnable, Thompson might just have become mayor.
The Bloomberg campaign engaged an aggressive effort to court ethnic communities, moderates, and independent voters. Full-page campaign ads dominated the local media, from major citywide dailies, to free neighborhood weeklies. And there was free media too, with 61 print publications endorsing Bloomberg.
On the local level, City Council Speaker Christine Quinn, a fellow Democrat, held out her endorsement until only a week before the election.
"There are a number of people around Bill who felt that he was let down and that, yes, it could have helped if President Obama had campaigned with him," one senior Thompson adviser told the Daily News.
At least some of Thompson's support resulted from voter outrage over Bloomberg's push to repeal term limits, a move that allowed the mayor to run for a third term. (He had previously opposed overturning term limits, as had city voters in two past referenda.) Thompson also sought to tap anger over the growing cost of living in the city, pushing an image of Bloomberg as an out-of-touch billionaire.
Relying on exit polls, the New York Times reports that 45 percent of voters said term limits were a factor in their decision to vote against Bloomberg, while about the same number cited his exorbitant campaign spending as an important issue.
In comparison to the ubiquitous Bloomberg advertising, Thompson at times seemed nearly invisible.
"I'm stunned," Baruch College Public Affairs professor Doug Muzzio told Politico of the close results. "Good thing [Bloomberg] spent $100-plus million -- unless the relentless multimedia barrage reminded folks that Bloomberg was an arrogant, out of touch plutocrat."
The mayor's backers pointed to indications of relatively low turnout to suggest that many potential Bloomberg voters sat out the election, expecting an easy victory. Looking ahead, Bloomberg's team says it is now focused on another pivotal local race, where a wealthy frontrunner currently leads 3-2.
"Whether the Yankees win in four or five or six or seven games, they are still the world champions," Bloomberg campaign spokesman Howard Wolfson said, according to the Daily News.