"The 'litmus test' for judicial appointments established by the Reagan Administration concentrated on a potential appointee's willingness to overrule Roe." (Morton Horowitz, Harvard Law Review, 1993) 

Really? Of the five justices sent to the Supreme Court by Reagan and George H.W. Bush, three voted to sustain Roe. Would any of the people put on the Court by Clinton or Obama vote to overturn it?  I have my doubts.  Who has a litmus test?