Is Congress more concerned with partisanship than in what is best for the nation?

From what I’ve seen over the last few years, it seems like politicians have largely disregarded both the best interests of the nation and the people who put them into office in favor of Machiavellian schemes, back-stabbing, sniping, and just plain-old playground fights.
The latest example of this I’ve seen is this Washington Post article about how the GOP is going to filibuster an Iraq/Afghanistan funding bill in a deliberate attempt to delay healthcare legislation.

So, am I just being jaded and cynical, or are they really more interested in spiting each other than in serving we the people?