Hugh McBryde makes the same argument...that someone needs to apply for a license for a second wife then sue the state when they deny the license. From what I remember Hugh seemed to think that the state would have to defend the individual seeking the right to marry a second wife because the state would be denying a fundamental human right (or something like that...I don't remember now)...I agree with you that Iowa would be a good place to start...unfortunately I don't know anyone in Iowa, much less anyone in Iowa with the moxy to take on the government...I think an interesting situation might be one where a woman left (legally divorced) her (christian) husband and he remarried...then later she wanted to reconcile with him. Should he be forced to divorce his second wife so that he could reconcile (remarry) his first wife, or ignore the scriptures he claims to follow and believe in?
1 Corinthians 7:10-11 To the married I give this charge (not I, but the Lord): the wife should not separate from her husband (but if she does, she should remain unmarried or else be reconciled to her husband), and the husband should not divorce his wife.
It does not say that the man is to remain unmarried, only the woman. Should his wife leave him and he takes another wife he would still be obligated to his second wife in the event that his first wife returned to him and wanted to be reconciled. I would think that this would provide an argument for the free practice of religion under the first amendment - after all it is a command from "(not I, but the Lord)". In this scenario wouldn't the state be preventing a man from freely practicing his religion; preventing him from obeying a direct command from his God?