Amna Nawaz:

Judy, those drills are intended to prepare students and teachers to protect themselves in the event of an armed intruder.

But, yesterday, the country's two largest education unions, the American Federation of Teachers and the National Education Association, joined with the advocacy group Everytown for Gun Safety to call for schools to change or end those drills.

For more on why, I'm joined by Randi Weingarten. She's president of the American Federation of Teachers, representing 1.7 million members.

Welcome back to the "NewsHour."