On Wednesday, House Minority Leader Nancy Pelosi sent a warning on the debt-ceiling hike. “Let’s get on with writing the bill,” she said. “I don’t need to see markets drop 400 points. But Republicans may need to see markets drop 400 points.” Pelosi remembers September 2008, when the House, then controlled by the Democrats, initially voted against the Troubled Asset Relief Program. Stocks plunged 778 points. Only after her caucus felt the visceral terror of an impending depression was Pelosi able to cobble together votes to counter Republican opposition. If the House goes to the wire this time, there will...