"As a law enforcement official, and given the situation unfolding in New York City, the DA didn't believe it was the right time for politics," said Eric Phillips, Rice's spokesman.
Phillips said Rice is monitoring the situation and will announce when it's appropriate.
The delay politically shouldn't hurt the Rice campaign, observers said Sunday. Joseph Mercurio, a Democratic consultant, said it's routine to hold announcements when they might be dwarfed by other news.
"It's not like there's an odd reason why she did it," Mercurio said. "That kind of thing happens all the time."
Some political observers noted that Rice, 45, of Garden City, has emerged as one of the stronger contenders in the five-person field vying for the Democratic nomination.
With the state Democratic Convention slated for May 25-27, Rice is close to getting the 25 percent of convention votes needed to automatically get on the ballot, observers said.
State party chairman Jay Jacobs said with Nassau, where he also leads the county party, and Suffolk behind Rice, she's already at about 15 percent of the convention votes. Jacobs said he expects Rice to get some support upstate and considerable support in the city, putting her over the top.
"I would be exceedingly surprised if she did not get on the ballot at the state convention," said Jacobs, who expects to endorse Rice in his capacity as Nassau party chairman either Monday or Tuesday.
"One is her resume, one is her gender and one is her geography," Cunningham said.
Cunningham explained that prosecutors appeal to the electorate, and Rice benefits from being the only woman now in the field. Though Rice once worked in the Brooklyn district attorney's office, she was elected in Nassau and Cunningham said that will help her draw suburban voters.
Larry Levy, who heads the Center for Suburban Studies at Hofstra University, added that not only is Rice's gender a plus, but her Irish Catholic background will help with the suburban vote.
Levy said Rice has something else important working for her.
"She's got the fire in the belly, too. There is no doubt about that," Levy said. "This is something that she really, really wants."