I’ve found that if I assme the worst, the most extreme that the left could conceivably go, I’ll rarely be wrong. History, especially recent history, shows us that they work incrementally. Sometimes when they think they’ve come close enough to the goal or gotten a majority of the people (especially the “youth” or the large army of gibme constituency) on their side, they make a dramatic final push. Sometimes when they think they have an unassailable leader (as in a minority or female), they make a push in spite of an opposed majority. Sometimes when they’ve overrached, they pull back from the termite tunnel they’ve carved and start another one. But they never accept the will of the people until they manage to get enough on their side. If they never do, and they get an “Obama” in place, they don’t care. But they never stop.
It’s harder for conservatives, because we’re not trying to forge new paths, we’re trying to protect the foundation.
For what it's worth, there's a lot to be said for a plan to scale back on your contributions to these plans anyway. The tax-deductibility comes with some strings attached that make these plans less flexible for an astute investor.