Republican lawmakers in Washington appear poised to approve sweeping tax legislation, which New York Governor Andrew Cuomo has dubbed an “economic death blow” to the state.

That blow, advocates say, could punch a hole in school budgets.

Schools across New York are already shortchanged billions of dollars, according to school-funding advocates, even as the state faces a $4.4 billion budget gap. The tax plan, if approved, has the potential to divert even more state and local funding from schools.

“I’ve been dealing with the state budget for more than 30 years and this is as volatile and uncertain as anything I can recall,” said Bob Lowry, deputy director of the New York State Council of School Superintendents.

The House and Senate must still combine their tax bills and pass a final version. Below is a guide to some of the worst-case scenarios for New York schools if that happens.

“Downward pressure” on local taxes

A provision of the tax plan would sharply reduce state and local tax (often called SALT) deductions a proposal that would hit high-tax states like New York hardest. The average SALT deduction in New York is $22,169, according to a report form the Governor Finance Officers Association, using data from 2015.

Advocates worry that voters whose tax burdens rise without the deductions will be less inclined to sign off on increases to their local school board budgets, which voters approve in most parts of the state. In New York City, school funding may be more insulated because residents do not vote on a budget.

However, the city could feel pressure to offset the lost SALT deductions by lowering local income taxes — a move that could shrink budgets across city agencies, including the education department.

“It stands to reason that there will be downward pressure for us to reduce our local taxes, which in turn would create less revenue for city services,” said New York City spokeswoman Freddi Goldstein in an email.

Flight of the super taxpayers

A small number of super-wealthy New Yorkers help keep the state and city governments afloat.

In New York City, about 25,000 families contribute more than 40 percent of the city’s personal income-tax revenue, according to the most recent figures analyzed by the city’s Independent Budget Office.

Their tax burdens could balloon without the SALT deductions, spurring a rush to lower-tax locales. While some experts said a mass exodus is highly unlikely, in a district where approximately 57 percent of school funding comes from the city budget, any significant loss of tax revenue could strike a serious blow to school funding.

“People who live on Park Avenue are not going to move to Alabama to pay lower taxes,” said Michael Borges, executive director of the New York State Association of School Business Officials. “But they may move to Scarsdale because they don’t have to pay a city income tax.”

A three-way “tidal wave of disaster”

Lost local revenue isn’t the only way school budgets could take a hit. In fact, it could be part of a triple whammy.

The tax plan would leave the federal government with a gaping $1.4 trillion deficit. Experts expect lawmakers may eventually plug the hole by slashing spending on healthcare and possibly other programs like education.

“It may result in lower federal funding for everything,” said George Sweeting, deputy director at the city’s Independent Budget Office. “If that happens, that would have an impact on federal funding for New York City.”

Still, school districts only get a fraction of their funding from the federal government. In New York City, federal money accounts for just 6 percent of school spending. (By contrast, 37 percent of the city’s education funds come from the state.)

However, federal spending cuts could have an indirect impact on New York’s education funding. If Washington provides less healthcare funding, for instance, New York could have to pick up the tab — creating a ripple effect, where it would have less to spend on schools.

The federal pressure would come at the same time New York is already facing a $4.4 billion budget deficit. Officials from Governor Andrew Cuomo’s office say the tax plan would be a blow to New York — but they also insist that Cuomo is committed to funding education.

Still, schools are staring at a “loss of federal aid, a loss of state aid, and a loss of local revenue,” Borges said. “It’s like a tidal wave of disaster.”

An under-the-radar change would cause “significant harm”

Finally, a little-noticed bond issue in the tax plan could cause New York schools pain.

Congressional Republicans would remove provisions that help schools borrow money for school construction projects, according to a letter signed by Board of Regents Chancellor Betty Rosa and State Education Commissioner MaryEllen Elia. The loss would “significantly harm districts’ finances,” it reads.

This measure would have a devastating impact on schools, school districts, local taxpayers and, most significantly, our students,” the letter continues. “That impact would be felt most dramatically by districts in poverty; in other words, the districts that would be hurt most are those that can least afford it.”