As calls were mounting for Anthony Weiner to quit Congress in the wake of his sexting scandal, a prominent voice joined the fray: former Gov. Eliot Spitzer, who had reinvented himself as a CNN talk show host after a prostitution scandal led to his own resignation three years earlier.

"I think that conclusion is absolutely right and I think that he almost owes it to his party right now to end this," Spitzer said on air in June 2011. "This is derailing the Democratic Party's effort to do whatever its agenda is. He should at this point resign."

Little did Spitzer know then that he and Weiner would be attempting political comebacks together at the same time: Spitzer, as a New York City comptroller candidate, and Weiner seeking to become the mayor of New York City.

Political observers are anticipating clashes between the two brash, ambitious Democrats that could snowball into a longer-term power struggle for control of the city. Already, Spitzer is emerging as a nuisance for Weiner. Spitzer's last-minute campaign announcement already has sucked up free press attention from Weiner, and his decision raised fresh questions about disgraced politicians' overall suitability for office. If elected, Spitzer could use his role to be a mayoral watchdog while potentially looking to run for the office on his own—possibly against Weiner.

"The way Eliot Spitzer is describing his approach to comptroller, there will inevitably be friction. I don't care who the mayor is," said Democratic consultant Maureen Connelly, who has advised mayoral candidates from Ed Koch to Michael Bloomberg. "You would think he's running for mayor himself. He's the sheriff," she added, alluding to his nickname as a Wall Street-policing attorney general.

The last thing Weiner needs is more buzz about sex scandals and political redemption. On Tuesday, Spitzer made news by choking up while talking about the personal "pain" he's been through in an interview on MSNBC's Morning Joe.

"Spitzer running is damaging for Weiner potentially not just because it takes the spotlight away from him but because he's gets lumped together with him," Connelly said. "Weiner already went through all the jokes about his sexting and now the whole thing is being dredged up again."

There are few published reports about Weiner and Spitzer intersecting while they were both in office. The two outspoken New York Democrats have rarely crossed paths—Spitzer served in Albany as attorney general and governor, while Weiner spent most of his political career in Washington. They marched in a pro-Israel parade together and joined forces to secure federal aid after a 2007 storm hit the city. In one of their only policy disagreements aired publicly, Weiner said he had "legitimate problems" with Spitzer's proposal to offer driver's licenses to illegal immigrants.

Though the comptroller is traditionally a little-known figure—can you name one?—Spitzer envisions raising the office's profile. Since 1961, nearly every city comptroller has gone on to run for mayor, but Abe Beame was the only one who succeeded. The exception was Elizabeth Holtzman, who served in Congress before becoming comptroller. The current crop of candidates for mayor includes Comptroller John Liu and former comptroller Bill Thompson.

Doug Muzzio, a public affairs professor at Baruch College in New York City, predicted a city administration that included Weiner and Spitzer would be "a heavyweight bout, a slugfest."

"The comptroller has fiscal responsibilities that act as a check on the mayor and city council, so the job is designed to get in the face of the mayor," Muzzio said. "Everyone views the comptroller's office as a stepping stone, and the mayor is the one who generally gets stepped on."

Recent history is ripe with examples. Koch feuded with his comptroller, Harrison Goldin, on issues from foster care to fire safety. Holtzman was known for embarrassing then-Mayor David Dinkins with tough audits. "Rudy always attacks people who stand up to him,'' said the 2001 television ad run by Comptroller Alan Hevesi against then-Mayor Rudy Giuliani. (He lost.)

Spitzer's abrupt entry into the race is widely viewed as a setback for Weiner. After catching up in the polls to the longtime frontrunner, Council Speaker Christine Quinn, Weiner has been trying to turn the page on his past, touting a 64-point plan "to keep New York the Capital of the Middle Class."

What's potentially bad for Weiner is probably good news for Quinn, who stands out as the only woman in the mayoral race.