To begin, what is an assassination? Of course, it is a type of killing. But whereas unjustified intentional killings are called “murders,” an assassination in some sense transcends that label. It is a targeted killing for some political, economic, or ideological reason; normally, of some prominent individual.
By contrast, in warfare, a sniper’s killing of a general or a king is not likely to be called an assassination.
Let me distinguish bottom-up and top-down assassinations. The assassination of a President or some government official is a bottom-up assassination, and these are the assassinations which we are familiar with. Here is a list: List of assassinations
However, when a ruler targets someone to assassinate, this goes by the euphemistic phrase of “targeted killing.” Lists of such attempted and successful assassinations (“targeted killings”) can be found here:List of assassinations by the United States; List of Soviet and Russian assassinations; List of Israeli assassinations.
See: Nils Melzer, Targeted Killing in International Law, 2008; Claire Finkelstein, Jens David Ohlin, and Andrew Altman (ed.), Targeted Killings: Law and Morality in an Asymmetrical World, 2012; Ronen Bergman, Rise and Kill First: The Secret History of Israel’s Targeted Assassinations, 2018.
Most such “targeted killings” have been covert. The first nearly overt one which caught my attention was the U.S. invasion of Panama by President George H. W. Bush on Dec. 20, 1989 in order to capture Manuel Noriega. To me this was worse than any “targeted killing,” because it involved the killing of needless American soldiers and some 500 Panamanian civilians.
After 9/11, with the so-called “war on terror” and the U.S. invasions of Afghanistan and Iraq, “targeted killings” became something like a common practice. Under President Barack Obama, Osama bin Laden, Answar al-Awlaki and his son were assassinated, and killing by the use of drones became a standard procedure.
The other assassination which looms large in my mind was that of Jamal Khashoggi in 2018, approved by the Crown Prince of Saudi Arabia, Mohammed bin Salman.
This practice of “targeted killings” as a strategy, rather than being a “war on terror,” has tended to create something approaching a totalitarian state of terror!
Given that most governments are in the hands of single rulers (be they monarchs, presidents, or prime-ministers), they tend to be ambitious, greedy, inept, or ruthless. And the intent of most assassinations of prominent officials is simply to get rid of a perceived evil vermin.
There is one prominent exception that I can think of. It is the assassination of Emperor Alexander II of Russia in 1881 by Narodnaya Volya. Their hope was not to kill a man, but to kill a system — to start a revolution, which did not materialize.