“It’s hard to extricate the White House from what’s happening in Chicago right now”

The American Federation of Teachers — the national parent organization of striking Chicago instructors — and the National Education Association boast a combined membership of 4.5 million. Democratic candidates up and down the ballot depend on teachers to hold rallies, staff phone banks and canvass neighborhoods in get-out-the-vote efforts that often make the difference in close races.

“In terms of putting resources up and boots on the ground, those unions are important,” said Steve Rosenthal, a longtime union organizer who is active in Democratic politics. “If they’re distracted, it’s not helpful. If there’s lingering anger and animosity, it’s not helpful.”

Rosenthal added that labor leaders could expect Obama to speak up on behalf of the teachers.

“It’s a high-visibility strike, and there are expectations that Democrats will stand with striking workers,” he said.