Ever hear of NATO?
Of which Turkey, a NATO member, borders Iran. A nuclear armed Iran is far more of a threat to Europe in the near to mid term than they would be to us. Send in the Brits, Germans, Italians, and Turks by land while we hit them from the sea and air. Six carrier battle groups and the American Air Force could level Iran's military capability in a six month aerial campaign prior to any land invasion.
