ALBANY – The Democratic speaker of the Assembly, Sheldon Silver, yesterday accused Mayor Bloomberg of political cowardice, suggesting that the mayor is obeying Governor Pataki and letting the state off the hook on resolving a multibillion-dollar school financing lawsuit.

Tensions further escalated as it emerged that the Democratic-controlled Assembly is planning to omit from its budget the controversial tuition tax credit that Mr. Pataki proposed earlier in the year. The Assembly’s expected removal of the tuition tax credit, which is heavily favored by school choice advocates, comes amid a ramped up effort on the part of the New York State teachers union to defeat the governor’s proposal, which would give a credit of up to $500 to low and middle-income parents of children enrolled in private and public schools.

Reflecting a widening split between Messrs. Bloomberg and Silver on the issue of school aid and political priorities, the Assembly leader yesterday faulted the mayor for forcing the state’s hand on the funding of school construction projects even while acting submissively as the state delays in complying with a state Supreme Court justice’s ruling in the Campaign for Fiscal Equity case.

“He has yet to publicly declare and call on the governor to stop appealing the CFE decision, which is the first place for him to get money,” Mr. Silver told reporters. “Yet the mayor, focused on politics and concerned about offending the leading Republican in the state, refuses to do that simple task – call on the governor to stop appealing CFE. So focused on cutting ribbons in schools or holding children hostage, the reality is, he has yet to speak up on the issue of operating money for the schools.”

As the final lap of state budget negotiations nears, it is becoming increasingly unlikely that state lawmakers and the governor will begin to comply with Justice Leland DeGrasse’s order that Albany infuse New York City’s public school system with billions of additional dollars in operating aid.

Yesterday, Mr. Silver, a steady ally of the teachers unions, appeared to be shifting blame for the lack of a resolution onto the mayor, arguing that Mr. Bloomberg’s quiet position on the lawsuit gave Mr. Pataki the freedom to delay.

The speaker’s attack on the mayor stems from their conflicting agendas. The mayor, on the one hand, has signaled that he is far more interested in getting the state to pay for half of the city’s multi-year capital plan than he is in pressuring Albany to obey the judge’s ruling, which ordered the state to give more money to the city to ensure that its students are receiving an education up to legal standards.

The judge is requiring the state to incrementally increase its operating aid to the city by $5.6 billion and to give the city more than $9 billion in capital aid, while Mr. Bloomberg is asking the state to give the city $6.5 billion in capital money over the next three fiscal years. By lowering his demands, Mr. Bloomberg seems to be accepting that he is more likely during his final years as mayor to see the capital plan money materialize than a payout from the lawsuit.

To get the capital money, the mayor has threatened to cancel the construction of dozens of schools, two of which are in Mr. Silver’s district and others in the districts of Republican senators, who have responded to the threat by hinting that the Senate’s budget will include the capital money that the mayor is demanding.

A spokesman for the mayor, Stu Loeser, issued a statement that made no mention of the CFE lawsuit and did not dispute Mr. Silver’s contention that the mayor has made the school construction projects his first priority.

“The Mayor feels so strongly about building new schools that last year he put up the $1.3 billion in school construction funds that the State failed to send us – above and beyond the $1.3 billion dollars for school construction we put up last year. This year we are putting in nearly another $1 billion, but New York City taxpayers just can’t afford to pay the billions of dollars in the State’s share of school construction costs anymore,” the statement said.

Mr. Silver, on the other hand, relies more heavily on the support of the teachers unions, which have taken up the CFE lawsuit with full force. The speaker has often said the state has a “moral obligation” to comply with the judge’s order and has demanded that Albany make a down payment during budget negotiations. His lashing out is also a reminder of the sore relationship between the two politicians and how much they’ve drifted since the earlier days of Mr. Bloomberg’s first term, when they were close friends and spoke of admiration for one another. The relationship frayed after Mr. Silver successfully derailed the mayor’s West Side stadium project.

Mr. Silver’s remarks come as he is trying to put himself in the best strategic position as budget negotiations enter the final stages. Yesterday, lawmakers disclosed that the Assembly was planning to unveil a budget that would not include Mr. Pataki’s tax credit proposal. Instead of a tax credit linked to tuition, Mr. Silver appears to be substituting into the Assembly’s budget a child tax credit of up to $300 that would not be required to be spent on educational expenses like tuition. Albany lawmakers are predicting that the final outcome will likely result in an education tax credit, but one even smaller than that proposed by Senate Republicans in their budget, which called for a statewide $400 tuition tax credit at a cost of $400 million.

Democratic Assemblymen pushing for the governor’s tax credit proposal said they were disappointed by the Assembly’s plan. “I’m all for tax relief, but I think we need to make a particular commitment to parents who invest in their kids’ education,” said Assemblyman Ryan Karben, who represents Rockland County, which has a large Orthodox Jewish population.

Assemblyman Vito Lopez, a Democrat of Brooklyn who is the most powerful backer of tuition tax credits in the Assembly, said he has “some serious concerns about the fact that the credit does not formally tie itself to education needs. “He said 80 to 90 of the 105 Democratic Assembly members support the tuition credits but are “afraid to come out on the record” because they do not want to oppose the United Federation of Teachers, the city teachers union.

Key to the survival of the credits will be support from Mr. Pataki. Mr. Pataki has previously indicated that the credits were among the important pieces of his budget. Also critical will be support from the Republican-controlled Senate led by majority leader Joseph Bruno. A higher priority for the Senate is preserving in the budget property tax rebates for New Yorkers outside of the city, sources said.

The most aggressive challenge against the tax credits appears to be coming from the state teachers union, New York State United Teachers, which lawmakers say has threatened to withhold contributions from those who support the measure. A spokesman for Mr. Silver said the Assembly had not completed its budget bills and would not comment on the child tax credit plan.