The charter school movement is split over the best strategy to deal with state lawmakers resistant to further expansion of the schools.

Charter school advocates disagree on whether they should be engaging or attacking their opponents in the Legislature, which is considering lifting the cap on the number of schools above the current limit of 100.

Those who support a more aggressive approach say lawmakers won’t act unless they are confronted with outside pressure and negative publicity. Advocates of tougher tactics have launched a statewide ad campaign that identifies by name specific lawmakers who are standing in the way of more schools.

The campaign has provoked concern among other leaders in the movement, who contend the attack strategy has failed to get results and has backfired by angering lawmakers. They are claiming that the Assembly speaker, Sheldon Silver, a Democrat, has threatened to cut off debate on charter schools until the ads stop running.

A spokeswoman for Mr. Silver yesterday denied that the speaker has removed charter schools from the Assembly’s agenda and said he plans to take up the issue next week following the Democratic convention in Buffalo.

The divide in the community comes as lawmakers consider Governor Pataki’s proposal to increase the maximum number of charter schools in the state to 250 from the current cap of 100 and exclude New York City from limits. Mr. Silver has said he is reluctant to support such an increase.

A group called Parents for Public Charter Schools, a 501(c)(4) advocacy organization affiliated with the New York Charter Schools Association, is spending millions of dollars on radio and television ads and direct mailings calling on the Legislature to lift the cap. It is believed to be the first major advocacy campaign launched by New York’s charter school movement.

The ads target specific lawmakers who are blocking efforts to lift the cap – in particular, Assemblyman Ron Canestrari, a Democrat who represents a district in Albany. One radio ad that has aired in Albany features an angry parent lashing out at the assemblyman.

“That’s why I am so mad to know that Assemblyman Ron Canestrari is ‘dead set’ against letting any more parents choose public charter schools for their children,” she says. “Not everyone can afford to send their children to private schools like the one he attended. That’s why options like public charter schools are so important to moms like me.”

With six charter schools in operation and three more set to open by the fall of 2007, Albany has the second highest percentage of students attending charter schools among New York’s cities. Public school aid follows students to the school in which they enroll, so when a student transfers to a charter school the district loses thousands of dollars.

The ad has provoked a furious response from the New York City Center for Charter School Excellence, a nonprofit group established in 2004 under Mayor Bloomberg with private money.

The chief executive officer of the center, Paula Gavin, has alerted Mr. Silver and other lawmakers that her group is not connected with the campaign and was not told about it in advance. She has communicated to members of the charter school community that her group strongly opposes its message, which she said risks alienating those members of the Assembly who had been warming to a lifting of the cap. She is also warning advocates that Mr. Silver has terminated talks on the schools as a result of the ads.

Her fear is shared by one of the most ardent supporters of charter schools in the Assembly, Sam Hoyt, who represents Buffalo. He said Assembly members are resentful of ads attacking one of their own and have fallen into a “circle the wagons” mentality. “I know Shelly Silver, and I know my conference. More than anything else, it will make them dig their heels more,” he said.

He said the Assembly has not taken up the issue of charter schools at conference meetings since the ads began running a little more than two weeks ago. He said it “appears” that Mr. Silver has put off discussion. The conference has discussed raising the cap twice this month.

An ally of the campaign, Thomas Carroll, the president of the Foundation for Education Reform and Accountability, said the charter school community is running out of patience and wants results.

“A number of charter school advocates believe the case for more charter schools should be made more aggressively and that’s what the ads reflect. It’s no different than the millions of dollars that the health and the teachers unions have spent making their case as well,” he said.

The chairman of Parents for Public Charter Schools, Bill Phillips, who is president of the New York Charter Schools Association, was not available for comment yesterday.

New York has 79 active charter schools, which enroll about 22,500 students. Twenty-one more schools are to open in the fall. Forty-seven of those schools are in New York City.