John McCain and Barack Obama both say they don't like litmus tests.
Yet McCain essentially says someone who supports abortion would not be on his list of judges qualified to sit on the Supreme Court. In other words, that's a litmus test.
Obama says he supports abortion rights, and he would look for judges with a world view. It doesn't sound like a litmus test, but Obama doesn't answer the question directly.
So, yes, Obama seems to have a litmus test, too.