At a (tellingly) off-camera briefing with the press, White House economist Larry Summers pulls out, in David Corn’s words, the “big gun.” Failing to pass the Obama-McConnell deal, he says, will ”materially increase the risk the economy will stall out and we will have a double dip.”

UPDATE: More from Summers via Jake Tapper:

“If this process were to break down and a bill were not passed,” Summers said, not only would economic projections recently revised upwards not happen, “downward revisions would commence.”