A saying in Washington is 'where one stands depends on where one sits'. Say that, in general, Democrats tend to favor unions and environmental regulation, unless you live in a coal mining state like West Virginia. In that case, 40% of the voters voted for an inmate imprisoned Texas rather than the incumbent president as a protest against Democrat environmental policies.
If the voter turnout in party primaries (where each party selects their candidates) is low, voters tend to be 'ideological' - therefore social conservatives against abortion and gay marriage vote for 'hard right' Republicans and labor union members and environmental activists vote for 'progressive' Democrats. 'Middle of the road' voters don't show up until the November general elections, at which point they are left to choose between 'hard left' and 'hard right'. The current system has tended to exclude 'moderates'.
Most of the US political establishment is now focused on domestic matters, including unemployment, education, health care, and regulation, where partisan divides are stark. How certain international adventures work out is a different matter - it will be interesting to see if consensus forms around actions relating to Syria, for example. At present, the US isn't paying much attention to Egypt, for example, where policy is still on automatic pilot. This is something that 'should be' addressed, but will probably wait until budgets are passed in the next month or so.