When President-elect Donald Trump announced Betsy DeVos as his pick to lead the U.S. education department, one thing became clear: His stated interest in channeling public dollars into private schools would be championed by a full-throated believer in privatization.

But could Trump’s promise to launch a $20 billion national voucher program for low-income children — bolstered by billions in additional state funding — ever take hold in New York City?

The short answer is yes, according to education experts, though it would likely face a number of political, logistical, and legal obstacles that would make a large exodus of public school students into New York City’s private schools unlikely.

One central challenge is the state legislature, which probably wouldn’t approve the billions of dollars necessary to implement a competitive voucher program.

Under Trump’s proposal, which is light on details, states would have to pony up to make the program work. Assuming Trump finds $20 billion to spend on vouchers, perhaps by reallocating Title I funding, that would by itself yield less than $2,000 per student living under the federal poverty line nationwide. That leaves much of the funding burden on the states — so if the legislature refused to support the program, it would limit the program’s reach (after all, $2,000 wouldn’t buy you much private school).

A voucher program in New York “would require a lot of political support, more so than is here now,” said Aaron Pallas, an education professor at Teachers College. He noted that the state legislature has even refused to approve a much softer measure to make certain donations to private schools tax deductible. “It’s unlikely a DeVos appointment is going to change that political calculus,” he said.

The state legislature would likely also have to overcome an unusual alliance: politically influential teacher unions and charter operators who might unite over the fear of losing public funding.

But even if the legislature did fund the program, state law could bar that money from going to the vast majority of the city’s private schools. That’s because the state constitution in New York — and roughly three quarters of all states — currently prohibits funneling public money into religious schools, according to David Bloomfield, an education law expert at Brooklyn College and the CUNY Graduate Center.

In New York City, 616 of the city’s 810 private schools are religious (76 percent), according to state data, meaning the pool of schools that could accept vouchers may be limited. (An important caveat, Bloomfield noted, is the U.S. Supreme Court has ruled that federal funding can be used on religious schools, leaving open the possibility that parents could use federal money to send their kids to religious schools. Still, federal funding alone is unlikely to give parents enough purchasing power to compete in the education free market Trump’s proposal envisions.)

Even if a voucher program cleared all of those roadblocks, “There would also be a capacity issue,” said Sean Corcoran, an education and economics professor at New York University. “To my knowledge, there are not a lot of private schools with extra space.”

Despite those obstacles, however, a voucher program in New York City is far from impossible. For one thing, there are lots of private schools (roughly 20 percent of the city’s students already attend them). And vouchers have even been tried, to some extent: In the late 1990s New York City experimented with foundation-funded vouchers, though they did not produce dramatic gains in student achievement.

“I think it’s actually more of a threat than most people think,” Bloomfield said. “Even without a state supplement, [federal dollars] could provide a subsidy for families who are looking to opt out of the public school system.”

Without specifics about how much the vouchers could be worth, it’s hard to predict the extent to which they could incentivize families to make different education decisions. But, Bloomfield said, if the Trump administration were to reduce Title I funding in favor of vouchers, the city could see a reduction in the “quality of public schools [that would] drive more students to the private market.”

Halley Potter, a fellow at the Century Foundation who studies education inequality, echoed that thought. “Even a moderately funded voucher program would give parents some options,” she said. “I don’t think we can just write it off as not plausible.”

Though Potter noted vouchers are “highly unlikely” to get much political support in New York City, the effects of a modest program could be noticeable.

“The biggest risk of a private school voucher program is the public accountability that ensures that parents are really getting access to quality options, and ensuring kids of different backgrounds have a chance to learn together falls by the wayside,” Potter said.

“There would be a lot of political opposition to it, but as with [the Obama administration’s] Race to the Top, there are a lot of things states will do for the money.”