How Far Can the Muslims Reciprocate?

There is no clear cut line about this and it's something we need to leave to the scholars of every era to discuss how much reciprocation is allowed you know as long as the Shah at of Islam are not compromised. As long as we don't have to worship false gods or do haram right to defend with life limb and property  this is something the scholars will decide that to what level can we go to is a very deep question.