A while back, as the sequester took hold and Obama unfurled his budget, Greg Sargent framed up what he presented as a tough choice for Democrats (on the dubious chance that they would have any choice at all): Stand pat with the sequester in place, Medicare and Social Security left essentially untouched, and no new revenues beyond the $600 billion over ten years enacted in January -- or sign on to a grand bargain that would include entitlement cuts proposed in