Get the federal government out of the business of defining marriage by only recognizing civil unions.

Have the federal government only recognize civil unions in all cases (same sex and "traditional") leaving it up to individual religious organizations to determine if they would like to recognize same sex partnerships as marriages. This would remove the arguments from both sides, those in favor of same sex marriage who are not content with civil unions because it sets up "separate but equal" legal definitions would loose this argument since it would be equal. Those in favor of "traditional marriage" would have to argue that the federal government is the final arbiter of who can marry instead of churches and would be arguing for more rights above and beyond what others are getting.