Here are some alarming facts:
The Center for Voting and Democracy releases predictions for most House races a year prior to each election (titled Monopoly Politics). In 2000, they had a 99% success rate.
In the 1998 election, 94 districts (22% of the House, then) were so safe for incumbents that the other major party didn’t even present a challenger. In 2002, only one incumbent House member lost to a non-incumbent challenger.
Keep in mind this was prior to 2010 redistricting and Citizens United v. FEC. If you wonder why certain House or Senate races draw so much funding or spending, it is because there are so many noncompetitive districts, and Citizens United then makes the spending all the more outrageous.
If we wonder why politics have become so much more hyper-partisan it is primarily due to the rules we’ve established that govern elections. The rules for how districts are created, who can vote, who can run, the fact that it is winner take all instead of ranked by preference proportionally, and the rules for how money is involved. Then, alas, the media just goes with the money wagon…that is TV and most radio media (there are still good periodicals and programs and journalists out there if you bother to look).
If we don’t change the rules that govern how elections operate, I’m afraid we won’t see a decline in hyper-partisanship.
(Source: “Reforming the Republic: Democratic Institutions for the New America”, by Donovan and Bowler)