Like it or not, the United States is a member of the UN. If the C-in-C decides to order American troops to serve in a peacekeeping mission, then they have to obey.
You say a 20 year old conviction doesn't bother you. Thats good, but a conviction is a conviction. You can't have it both ways.
George Bush stopped drinking over twenty years ago, Michael New had two drug arrests less than five years ago within the span of a year. Big difference...
Oh and let me ask this again, have you ever done anything against the law?
Nothing worse than speeding tickets.