Litmus Testing keeps the party ideologically pure.
It makes absolutely no sense. The are parts of the country where Social Conservative cannot win. In those ares you need to have moderate Republicans run. Yes, they may be pro-choice or pro-gay marriage, but at the same time, there are a lot of Republicans that are tha way as well. Are you willing to get rid of Republicans who are socially moderate or liberal? If so, like I said, get ready for a lifetime of Democratic control of Congress.