Ezra Klein explains the perverse logic of our current political dynamic:
These two problems get to the essential difficulties confronting the nation: There is no doubt that minority parties generally profit in elections when the unemployment rate is high. But given that reality, what incentive do they have to help the majority party lower the unemployment rate? Further out, there is no doubt that the majority party has an incentive to prevent a fiscal crisis on its watch. But what incentive does the minority party have to sign on to the screamingly painful decisions that will avert crisis?
In most political systems, it doesn’t really matter that the minority has no incentive to help the majority. What the minority does is outline an alternate policy dynamic, try to make hay out of scandals, and generally wait in the wings to seize the opportunity to take over if the majority can’t deliver the goods. But the US political system actually affords the minority substantial opportunities to prevent the majority from delivering the goods.
At a time when the strange politics of the apartheid south led to low levels of congressional polarization this wasn’t a large practical problem:
Those days, however, are gone and it’s not clear what would bring them back. People sometimes suggest that gerrymandering is the culprit, but political science disagrees. What’s more, though people may find polarization in the House of Representatives aesthetically displeasing, the practical problem arises from the intersection of the filibuster and polarization, and gerrymandering isn’t an issue in the Senate.