Donald Trump announced a $20 billion federal school choice proposal last week and the major nationwide teachers’ unions, who have both endorsed Hillary Clinton, are predictably mad about it.

Trump described his plan as a block grant to states, where each state would develop its own formula for funds distributed to students in poverty to use at the public or private school of their choice. States would have the option of participating, though Trump said he would campaign for participation “in all 50 states.” He called on states to provide funds on top of the federal funds, providing up to $12,000 for each student.