Chicago might be the last stand for business as usual. Parents know it. Politicians know it. And, in their heart of hearts, the teachers probably know it, too. Perhaps they need a nudge from authority to move beyond the denial stage. Ordinarily, there’s no reason for the White House to get involved in local political disputes. But Chicago is President Barack Obama’s hometown, Emanuel is his former chief of staff and Duncan is the city’s former schools chief. Obama has so far declined to take sides. He should — and he should side with the future.