Wrong strategies and tactics do not make a nation great. The US entered Iraq on a wrong footing. Eventually Iraq is closer to Iran today than ever before. What did the US achieve by spending billions and sending many US men and women to death? Iraq is still unstable. The whole Middle East is now riddled with all sorts of movements without safeguarding the lives and properties of millions of inhabitants in the area.
What does President Trump hope to achieve by the murder of an Iranian General? If the Iranians and their supporters overreact they will also proceed to kill innocent citizens.
Assassination is not war. Many presidents of the United States died through assassination. No nation should therefore seek to show its might through assassination in the Middle East.
Iran and its supporters should not avenge the death of a general by assassinating other innocent citizens of the US. Instead they should take this matter up with the United Nations so that multi-lateral actions could be taken to prevent recurrence. In this way they will help to promote a type of world order where no state will simply impose its will on another.