Here is an article that I am almost entirely in agreement with:

Thomas Sowell on Judges on National Review Online
It is understandable that liberal Democratic presidents, beginning with Franklin D. Roosevelt, loaded the Supreme Court with liberal, Democratic justices.

What is far harder to understand is how a whole succession of conservative Republican presidents — Nixon, Ford, Reagan, and Bush 41 — managed to appoint so many liberals to the Supreme Court.

In the U.S. today there is no single person, including the President himself, who has the power of the nine Supreme Court Justices. The point Sowell is making here is that conservatives have abdicated their responsibility to hold the line on conservative appointments and the result has been that liberals have managed to take virtually total control of the nation’s legal system through the SCOTUS. This is because liberals vigorously (and venomously) oppose any remotely conservative appointment (such as Bork or Thomas) while conservatives rubber stamp any radical liberal appointment (such as Ginsberg).

I am not a “single-issue” political person, but if I were, this would be the single issue I would focus my vote on.