I want Members of Congress to lose sleep if they think they're doing something that their constituents wouldn't approve of. I want them to want reelection. If I was to really pick one thing that might be seriously wrong with the contemporary Congress, it's that the reelection incentive might not be strong enough -- if it was, perhaps Republicans during Bush's second term might have bailed on his unpopular policies. My guess, however is that the Republicans defeated in 2006 and 2008 (and the Democrats defeated in 1994) are doing just fine for themselves. Those Republicans may sleep well, but they ran their country into the ditch.
But one overwhelming reason they did was precisely because they worried about being out-machoed on the Iraq war and torture or pummeled by opposing the Medicare Prescription Drug Act, to name just three. I prefer Edmund Burke's advice myself. It's called representative - and not direct - democracy for a reason.