Regardless of whether one supports or opposes same sex marriage, the decision to recognize such unions ought to be made by each state rather than imposed as a one-size-fits-all mandate by the federal government. Any federal laws that prevent states from determining their own standards for marriage should be repealed; the federal government should not define marriage, whether by statute or constitutional amendment.
Well I suppose Mr. Barr would also favor letting states decide whether they should discriminate against women, minorities or the handicapped or perhaps he just thinks it's okay for states to discriminate against gays. In any event, his philosophy would leave in place all of Federal immigration laws that discriminate against me and keep me and my family out of the country right now. Strict constructionism of a constitution that was written 200 years ago fully supporting the enslavement of Africans and the disenfranchisement of women is either seriously disingenuous or otherwise out of touch with the progress of civil society that has occurred ever since.