Is it Sinful to Pledge Allegiance?

Does pledging allegiance to something such as a nation or flag have an object or subjective meaning? As Christians we should solely pledge allegiance to the Kingdom of God and his desires; however, as we discuss there may be particular situations in which an individual can make a pledge. But just like everything else, it may not be initially wrong intrinsically, if the oath or pledge of allegiance encourages sinful behavior it should be avoided.