With the polls bouncing around and front-runners changing by the week, Mayor Bloomberg has embarked on a re-election strategy that only an incumbent with limitless resources can afford: target the two candidates who, this early in the game, seem most likely to emerge victorious from the Democratic primary.

That’s why last week – as will be the case in weeks to come – New Yorkers were inundated with Bloomberg campaign advertisements that not only draw a bead on the Hispanic base of the one Hispanic candidate in the race, Fernando Ferrer, but also seek to woo women, a likely source of strength for the only woman seeking a major-party mayoral nomination, C. Virginia Fields.

“Bloomberg has enough money to spend where he can run an ad campaign that targets Freddy’s base and C. Virginia’s base and even the other candidates’ white base in one campaign all at the same time,” the president of political consultancy the Advance Group, Scott Levenson, told The New York Sun. “In fact, if he decides to, he can go after the Urdu speakers, the Chinese speakers, and all the other subgroups he needs to tap. He gets to make all those decisions because he has so much money.”

In 2001, Mr. Bloomberg reported spending $74 million of his own money on his mayoral campaign. At the time, he defended the gargantuan amount by saying he needed to spend more than other candidates because he lacked their name recognition. This time he has again opted out of the campaign-financing system, and he has already spent more than $10 million of his $5 billion personal fortune. Analysts said they expect he’ll spend as much as $100 million on this race. Mr. Bloomberg has said he will do whatever it takes to get his message out to voters.

A Quinnipiac University poll released this month showed Mr. Bloomberg pulling ahead of Mr. Ferrer, former borough president of the Bronx, for the first time. Comments Mr. Ferrer made on the Amadou Diallo case before an audience of police sergeants in March have hobbled his campaign.

Ms. Fields, meanwhile, has been climbing in the polls. Her rise has been so precipitous that Mr. Bloomberg’s campaign strategists are actually musing about the possibility of Ms. Fields’s winning the Democratic primary or a runoff with Mr. Ferrer, particularly if turnout among blacks and women is high. If she does prevail, analysts expect a kinder and gentler campaign.

Analysts said Mr. Bloomberg will tread lightly around Ms. Fields. In addition to his personal feelings about her – he clearly likes her – lashing out at a personable, black female candidate would make him look mean-spirited, analysts said. So Mr. Bloomberg, who has a tendency toward sarcasm, will try to hold his tongue where Ms. Fields is concerned.

“We’ll see him take a much softer approach toward Virginia,” a longtime political strategist, George Arzt, said. The change, however, would be more in tone than in strategy, Mr. Arzt predicted.

“Quarterbacks have something called a touch – they need to be able to throw all the way down the field as hard as they can, but to be good, they also have to have a soft touch, the dump pass,” Mr. Arzt said. “Politics works the same way.”

A political consultant who works mostly with Democrats, Hank Sheinkopf, said: “After his Diallo comments, Freddy is damaged goods and Virginia is tough to assail. In a city where gender is not insignificant and race is always at the edge of the discussion, Virginia is a serious threat, and Bloomberg knows this. That’s why he is working on getting positive media on his accomplishments, so it becomes less likely that any opponent post-primary can gain traction. That’s what he is doing, and that’s a smart strategy.”