Is it possible for the retired US military to take a tour of Iran?
Everyone can apply for an Iran tourist visa to visit Iran until being on a tourist passport. Then you have to wait if your visa is rejected or approved. The US citizens have to take part in a guided tour and wait for about a month to get a response from the ministry of foreign affairs.
If you need an Iran travel package, get in touch with us. You can find all details about Iran visa on this page: Iran Visa Requirments