WASHINGTON (Reuters) - The Republican leader of the U.S. Senate said on Sunday he supported a constitutional amendment that would ban gay marriage. Reuters Photo Senate Majority Leader Bill Frist expressed concern about the Supreme Court's decision last week to strike down a Texas sodomy law. He said he supported an amendment that would reserve marriage for relationships between men and women. "I very much feel that marriage is a sacrament, and that sacrament should extend and can extend to that legal entity of a union between, what is traditionally in our Western values has been defined, as between a...