Once again, the Trump administration has made expanded school choice the signature initiative in its education budget proposal. But there might be some confusion out there in terms of how it’s supposed to operate. Let’s try to clear that up.

In the president’s fiscal 2019 budget pitch, there’s a $1 billion “Opportunity Grants” proposal designed to boost both public and private school choice. However, the budget blueprint doesn’t assign any specific amount of money to either public or private school choice.

The reason? It’s a more-fluid version of what Trump proposed last year for fiscal 2018.

In the fiscal 2019 proposal, states could apply at their discretion for the $1 billion in “Opportunity Grants” funding. So a state that already has a robust school choice program could seek a chunk of that change to increase the cash available for what they already have, in theory.

Districts could also apply for some of that $1 billion. But they would be doing so under the Every Student Succeeds Act’s weighted student-funding pilot. Under the terms of that pilot, districts can combine federal, state, and local sources of money and repackage it so that the new funding stream “follows” the student. It was put in ESSA to help districts with high-needs students—think English-language learners, for example.

This pilot isn’t strictly “school choice” in the way some are used to interpreting it—for one thing, student or parental choice isn’t explicitly mentioned in ESSA’s language about the pilot. But it could allow districts interested in operating public school choice programs to begin exploring it, or to build on weighted-funding systems they already use. Secretary of Education Betsy DeVos seems excited by that prospect: She recently opened up the pilot to districts interested in applying. And the department seems to be think of this as an “open enrollment” system.

By contrast, for fiscal 2018, Trump proposed $250 million in grants to states operating private school choice program. He also sought a student-based budgeting program under the Title I umbrella for 2018, to the tune of $1 billion.

Unlike with states, there’s no substantive reason to think districts would be interested in using this new funding in order to direct it to private schools. But the Trump proposal does set up an interesting hypothetical in which a state could apply for some of that money to create or increase a voucher program, while a district in the same state could apply for the weighted-funding pilot. How much of that money would ultimately go to private schools, and how much would go to public schools?

All of that, of course, assumes the $1 billion proposal will get any traction. Remember, Congress ignored Trump’s school choice proposals for fiscal 2018. But the new proposal could theoretically tempt some districts to throw their hats into the ring for the funding pilot.