Ezra Klein cooked up a good one.
Imagine that John McCain had won the 2008 election [and] … decided to co-opt a longtime Democratic priority and reform the health-care system.
… How many Republicans would support the bill if it were their party that looked likely to benefit? How many House Democrats would stick with the plan if it was taxing some benefits and had no public option and a Republican president had his name on it? And if you think that the differences in vote composition would be dramatic — and I do — then what does that say about the usefulness of evaluating legislative fights on grounds of policy disagreements?
Maybe it isn’t so much that Congress is the graveyard for good ideas but that it isn’t even about ideas. They can only get through the iron gate by coincidentally being politically viable (for which the party affiliation of the president matters). I think I’ve just about said that before.