I just don't think that's true. When conservatives had a clear message and ran an excellent campaign, they overwhelmingly won (unless they were sabotaged by the RINO elite). The problem is that when they get to DC too many go over to the dark side.
It's the RINO elite that can't win. They don't give anyone a reason to vote for them.
What exactly was wrong in the messages of:
Ken Cuccinelli
Sharron Angle,
Christine O’Donnell
George Allen
Joe Miller
Ken Buck
Christine O’Donnell
Alan West
Barry Goldwater
??
All of above were good, consistent conservatives.
Problem was voters were not.