Using your logic, Tancredo should have gotten slaughtered in this election, however, he won handily.
No matter, how many ways you try to spin it, Republicans did not lose by being too conservative.
Tell that to J.D Hayworth who in his last 3 elections won with 60% of the vote, but in 2006 after he jumps on the Tancredo bandwagon and is on Imus bashing the President, he loses.