Governor Spitzer is setting the stage for a deal on an expansion of charter schools in the state, unveiling compromise plans on two key issues dividing charter school advocates and the teachers’ unions.

One of the issues concerns the legal process by which teachers at charter schools can decide to unionize, a sticking point in the failed negotiations in the last days of the Pataki administration.

A top aide to Mr. Spitzer said the governor favors secret-ballot organizing elections as long as the elections are free of voting “irregularities” — a position supported by the New York City schools chancellor, Joel Klein.

Charter school advocates contacted by the Sun responded positively to Mr. Spitzer’s labor proposal. The president of the New York City teachers’ union did not respond directly to the plan but seemed to indicate that it addressed some of her concerns.

The United Federation of Teachers, a major interest group in Albany, has said it would not support lifting the statewide cap on charter schools unless the state’s charter school law was changed to better protect teachers who want to form a bargaining unit. Charter school advocates say that having teachers who work outside the standard public school union contracts allows them flexibility — longer school days, better ability to fire bad teachers — that yields better results for students.

The president of the New York City teachers’ union, Randi Weingarten, has been pushing to replace secret ballot organizing elections in charter schools with a card check election. Under a card check process, union representatives collect signed cards from teachers until they have a majority of support, triggering certification by the Public Employment Relations Board. Critics say the card-check system exposes workers to union intimidation and peer pressure; advocates say it protects workers from anti-union campaigns by management.

Most of the roughly 100 charter schools in the state are not unionized, though two are run by the UFT itself. Under existing law, teachers can conduct a secret ballot election if 30% of the faculty members submit cards to the PERB expressing interest.

In his final weeks in office, Governor Pataki failed to broker a deal with the Democratic speaker of the Assembly, Sheldon Silver, on a charter school expansion.

Before leaving office, Mr. Pataki, who wanted to raise the cap to 250 from 100 and give Mr. Klein the power to authorize 50 schools on his own, warned that Mr. Spitzer would succeed in lifting the cap, but lawmakers would “gut the bill by giving the special interest groups a lot more control over how those charter schools are run.”

On Friday, Mr. Spitzer’s communications director, Darren Dopp, said the governor “supports secret ballot elections at charter schools unless voting irregularities are found by PERB in connection with an organizing election. If irregularities are found, PERB would then authorize a card check election, which means that the union would be recognized when a majority of the members of the bargaining unit signed a card expressing their interest in joining a union.”

The president of the New York Charter Schools Association, Bill Phillips, told the Sun that his group viewed Mr. Spitzer’s proposal as a “promising development.” He said he would like to know how an “irregularity” is defined and whether under the Spitzer plan “management has a presumption of innocence.”

Ms. Weingarten in a statement said, “We support strong sanctions to stop employers dead in their tracks from firing teachers who want to join a union. It’s not about secret ballot elections. It’s about protecting teachers from retaliation.”

Charter school advocates say a book-length teachers contract would stifle flexibility and innovation, turning independent charter school into an ordinary public school. They argue that charter schools perform better because they are able to rapidly fix what’s broken, for example, by changing teacher schedules, redeploying staff, or firing under-performing teachers without engaging in contract negotiations that could take years.

Unions say the card check process guarantees the right of employees to unionize by preventing management from retaliating against teachers who want to join a collective bargaining unit.

In his January 3 State of the State address, Mr. Spitzer offered a compromise plan on another issue that has held up an agreement on the schools. In upstate New York, opponents of charter schools have expressed a fear that charter schools pose a threat to school districts by consuming public dollars.

In his speech, Mr. Spitzer called for lifting the 100-school statewide cap on charters. He said an expansion of the schools “must be accompanied by transitional aid for districts — like Buffalo and Albany — that have been most affected by a high level of enrollment in charter schools.”

In school districts, such as Buffalo, a greater percentage of students attend charter schools, meaning that a greater share of public dollars follows the students to the schools. Mr. Spitzer is proposing to make up some of that difference.

There are about 14,000 students attending 58 charter schools in New York City.