Is Elizabeth Warren the Face of a Democratic Crackup?

I've heard from a few people lately that the Democratic Party is headed for the same kind of intraparty demolition that continues to plague Republicans. According to this view, Democrats haven't reckoned with the looming entitlement disaster that will pit the party's moderates, pruning shears in hand, against its left, which will latch onto current Social Security and Medicare funding like a militant tree hugger around an ancient sequoia.

In addition, the left is furious at President Barack Obama for snooping on, well, apparently everyone and everything on the planet, and they will demand a politically perilous retrenchment of the national-security state from their next presidential nominee.