While I understand the fear, anger, and rage that would move someone like Eli Wiesel to say this, I wish he hadn't.
Elie Wiesel (orange box) in the Buchenwald, Germany concentration camp, April, 1945, after liberation by the U.S. Army. (Public Domain photo by U.S. Army Signal Corps photographer.)
Not only would assassinating Ahmadinejad not solve the Iranian problem, it risks unleashing a wave of retaliatory assassinations of other heads of state.
The world informally agrees that states do not target other heads of state for assassination.
After WWII, states reexamined that position, wondering if they had assassinated Hitler the horrors of the Holocaust could have been prevented.
During the Cold War in the 1950s and 1960s, heads of states were targeted for assassination. One of the unintended tragic consequences may have been the assassination of President Kennedy.
Some scholars speculate that among Lee Harvey Oswald's motivation was retaliation for the attempts the CIA was making against Fidel Castro and other Cuban leaders. Oswald was an unaffiliated communist who strongly supported and sympathized with the Cuban revolution.
Many options such as more sanctions especially cutting off refined oil products, a blockade, or a declaration of war, are available to stop Iran from acquiring nuclear weapons and supporting the Iranians' demands for freedom.
Assassinating their leaders is not one of them.
Related note:
Assassinating Hitler would not have ended the war. That would have not changed the demand by the Allies and the Soviets that Germany unconditionally surrender, be occupied and disarmed.
The Allies and the Soviets would have preferred to capture Hitler alive then try him war crimes.
The German anti-Nazi resistance was divided on assassinating Hitler. Some felt that assassination was necessary for a successful coup and to end the war. Others, perhaps Rommel, preferred arresting Hitler then holding a public trial to break the Nazi hold on the German psyche and to began to restore Germany's standing in the world by taking responsibility for their crimes.
For more information:
Eli Wiesel's account of his Holocaust experiences and his post war recovery.
