Gary Bauer of American Values writes in Human Events:

By invoking “states' rights,” some Republican presidential contenders argue that national efforts to protect normal marriage and unborn life betray the federalist principles at the heart of conservatism.

I’ve always believed that the government that’s closest to the people governs best.  But the definition of society’s most vital institution and the protection of its most vulnerable persons are so basic to our understanding of democracy that they must be taken up nationally.

... I believe that ultimately there will be a national policy on marriage and abortion—not 50 separate policies in the states.  This belief only underscores how important it is that those seeking to lead the party, and the country, articulate clear positions on abortion and marriage that respect not only our Constitution but also our most fundamental values.

Any politician who tries to give the “it’s a state’s rights issue” answer is probably either uninformed or disingenuous, because the Left will not permit each state to decide, and will use the courts to impose its views.  Such an answer is actually a slow-motion surrender, because liberal social activist will not take no for an answer.