With opinion polls suggesting Fernando Ferrer’s prospects for ousting Mayor Bloomberg from office are dimming, the Democratic nominee yesterday returned to the “two New Yorks” theme that he used in his unsuccessful Democratic primary race four years ago.

Although Mr. Ferrer resurrected the theme while speaking in front of a church congregation about a week and a half ago, yesterday’s speech at the Bronx Community College was his most formal and explicit embrace of language that was criticized as racially divisive in 2001 and that he has steered clear of for much of this campaign.

Several political analysts and observers characterized the move as an act of last resort. It came on the day that a new Quinnipiac University poll showed Mayor Bloomberg with a 31-point lead among likely voters.

“This is a political Hail Mary pass,” a professor of political science at Columbia University, Steven Cohen, said. “He is throwing the ball up and hoping somebody in the end zone will catch it. In a sense, when you are down this far and your opponent is somebody with limitless resources … you do anything you need to.”

With two weeks to go until the November 8 election, Mr. Ferrer, the former borough president of the Bronx, told the audience of how he was raised by a single mother and a grandmother, earned a scholarship to New York University, and then crossed a metaphorical bridge to the more opportunity-rich city.

“My friends, there are two New Yorks,” he said, according to his prepared remarks. “There have been two New Yorks my entire life. The work of my life has been to do whatever I could to bring them together.”

Later in the speech, he responded to anticipated criticism: “There will be those who call what I have said today divisive. They will call it class warfare, or maybe they will say it’s about race. Perhaps they do so for their own political purposes. If so, shame on them.”

In the past, he has said the theme is a matter of economic disparities, not race.

A spokesman for the Bloomberg campaign, Stuart Loeser, said in an email that the mayor has “worked hard over the last four years to bring New York City together and make it a City of Opportunity for everyone.”

However, City Council Member Letitia James, one of Mr. Ferrer’s supporters, said the mayor had failed on many fronts by shunning important legislation to help the poor.

She said she was happy Mr. Ferrer was talking about “two New Yorks” because the problem of increased poverty has not received enough attention in the campaign.

“I think he should have done it a long time ago, to be honest with you,” she said. “I think we should have done more to reach out to those pockets of poverty to energize those constituencies because they are a voting bloc.”

Ms. James said she thought Mr. Ferrer was probably “afraid of polarizing” the issue.

A political consultant, Norman Adler, said invoking the theme was a signal that Mr. Ferrer was trying to appeal to his base, Hispanic and African American voters.

“He is repeating something that didn’t work once and I have strong doubts that it will work this time,” Mr. Adler said.

A spokeswoman for Mr. Ferrer’s campaign, Christy Setzer, acknowledged that the Democratic nominee had been using the language more often lately, but said Mr. Ferrer has been talking about the same issues of poverty, education, affordable housing, and health care all along.

“It is a recognition of the fact that as we get closer to Election Day he is going to be speaking more powerfully, more strongly, and more clearly about the fact that too many people in New York are left behind,” Ms. Setzer said.