To eliminate graft and enable a Congressman to vote on principle the single most effective change would be for both Houses to pass a procedural rule that all amendments to a bill must be germane. Another way of stating this is that a bill can only have one purpose.
This would prohibit earmarks, reduce vote swapping incentives and produce simpler and better legislation.
Simple, very simple.
Wow, of anything I've suggested, I'd think this is the most sensible and practical.
It would stop 1/4 million dollar bridges and other graft with a very simple solution. It would also greatly simplify the legal code and encourage votes based on merit.
Common sense - the cure for stupid!
1 bill - 1 vote.
Toss in term limits for all elected officials and congress might become "of the people, for the people".