Our current political system is like a game where the players make the rules to suit themselves and change them whenever they like. The recent example of Tom DeLay redrawing the congressional districts in Texas to make it impossible for Democrats to win is but one of many examples. Once a congressman gets in office they tend to stay term after term because they have designed the whole system to protect incumbency.
How many remember all the talk about "term limits" back in '94 when the Republicans finally won control congress? But oh how quickly "term limits" was forgotten when they got in power!