Will the Democrats have their own Tea Party rebellion?

At hand were two provisions added to a last-minute, must-pass government-funding bill that would prevent a shutdown. Democrats were comfortable with the 1,603-page legislation except for two late-breaking provisions: one that would change the Dodd-Frank bank regulation bill, and one that would let donors give more cash to national political parties.

Things started looking tricky for the president when Sen. Elizabeth Warren, a liberal Massachusetts Democrat who’s made battling Wall Street her signature issue, came out vocally against the bill.

All of a sudden a wing of the president’s party appears to be hyperprincipled, unpredictable, and eager to buck leadership.