An argument I've been hearing recently is that Christine O'Donnell and Sharron Angle cost Republicans seats because they were poor candidates or would have been too conservative for their constituents. As that logic contends, Sue Lowden and Mike Castle - the establishment, moderate, non-tea-party candidates - would have won.
Primary voters presumably face such a choice in every state, so let's extend that thought and consider a hypothetical Senate in which Republicans could either elect 60 moderates or 40 hard-core conservatives.
Given these premises, would you rather win with more moderate candidates or lose with more conservative ones? In essence: would you rather have 60 Lindsay Grahams or 40 Jim DeMints?
40 Jim DeMints would certainly represent a more conservative vision of government, but they would never win a single vote on legislation. It would also be impossible to get 60 Jim DeMints elected.
60 Lindsay Grahams would be interesting. While your "side" would win 100% of the legislative battles, conservatives might not like the results.
On one hand, you have a moderate but unreliable Republican supermajority, and on the other a vocal minority of strong conservatives.
Such a calculation is going to be implicit in the 2012 cycle, when twice as many Democrats are up for election as Republicans. It is going to be a great opportunity for Republicans to take the Senate, but it will also ignite debate over party's ideological purity.
So which would you pick? 60 Lindsay Grahams or 40 Jim DeMints?