Meanwhile, Hillary Clinton faced more criticism from teachers during a speech at the National Education Association’s assembly Tuesday, when she provoked booing from unionized teachers by suggesting public schools and charter schools work together to improve education.

Hillary Clinton: “When schools get it right, whether they’re traditional public schools or public charter schools, let’s figure out what’s working.”

Teachers: “Boo!”

Hillary Clinton: “No, let’s figure out what’s working, and share it with schools across America. We can do that. We’ve got no time for all these education wars.”

The National Education Association is the largest teachers’ union. Its leadership endorsed Hillary Clinton in 2015, despite protests from some of its rank-and-file members who supported Bernie Sanders.