While a few lesser-known officials have announced their candidacies, Dart is the first candidate with enough citywide stature — not to mention experience in Chicago's hardball politics — to be a formidable contender.
Two people close to Dart told The Associated Press on Wednesday that the sheriff — who received national headlines for suing Craigslist and halting court-ordered evictions — has decided to run for mayor.
"He's all the way in," said one person, who spoke on condition of anonymity because the person was not authorized to talk publicly about Dart's plans. "He's decided to run."
Dart's decision puts him toward the front of a pack of potential contenders exploring a campaign to replace Daley, including White House chief of staff Rahm Emanuel, U.S. Rep. Jesse Jackson Jr. and former U.S. Sen. Carol Moseley Braun.
Dart, who also is widely expected to win a run for re-election in November, said only that he's "very strongly considering" running for the office after Daley's surprise Sept. 7 announcement that he won't seek another term.
With ample name recognition and a strong political organization to help get out votes, Dart should be able to mount a formidable campaign, analysts said.
Dart, 48, is in the process of putting together a campaign staff and has started circulating petitions to get 12,500 signatures needed by late November to put a candidate's name on the ballot in the February primary, the first person said.
He's also been calling public officials and business people to tell them of his decision to run, the person said. A Chicago businessman and close Dart friend, also speaking on condition of anonymity because he did not want to pre-empt the sheriff's announcement, confirmed he had received such a call from Dart.
Other potential candidates are as well known as Dart, if not more so. Topping the list is Emanuel, who in recent days has been calling and meeting with other potential contenders to discuss the race.
Another high-profile potential candidate is Braun, the only black woman to ever serve in the Senate. She is circulating petitions, though she has yet to declare her candidacy.
Jackson also is considering a run, but his candidacy is in doubt amid recent allegations he directed a businessman to pay former Gov. Rod Blagojevich millions of dollars if he appointed Jackson to fill President Barack Obama's vacated Senate seat. The businessman also said Jackson asked him to buy plane tickets for a woman described as a "social acquaintance" of Jackson's.
Analysts say Dart would be a strong candidate in large part because of the kinds of headlines he has made in recent years. A former Cook County prosecutor and state lawmaker — but never a lawman himself — Dart landed on Time magazine's list of 100 most influential people last year for popular but some decidedly un-sheriff-like moves.
In 2008, for example, he stopped sending his deputies out to enforce court-ordered mortgage foreclosures because many of those forced from their homes were low-income renters who faithfully paid their rent. He started up the evictions again only when banks agreed to what he considered a kinder, gentler eviction process.
Last year, he sued Craigslist, alleging the online classified site has created the "largest source of prostitution in America." He brought with him to that news conference a 19-year-old woman whom he said turned to prostitution after going on the site in search of modeling jobs. He also told of his detectives posing online as minors seeking sex on Craigslist.
A federal judge ultimately threw out the lawsuit, but not before it made national headlines.
Dart built on his reputation as a protector of the vulnerable when his office launched an investigation into an alleged scheme by workers at a historic black cemetery to resell burial plots after discarding the original remains inside.
He can also be a savvy politician, analysts say.
"He has organized vast sections of the city for Daley and for his own campaigns," said Don Rose, a Chicago political analyst. "He knows the game very well."
Dart also would have a solid Democratic organization to work for him from the moment he make a formal announcement, analysts say.
"He does have a couple hundred guys he can put on the streets any one time," said Thom Serafin, a Chicago political analyst. "(He has) one of the few organizations left in town with foot soldiers."