Sure, there was the attempted assassination of Reagan and the fears for Obama as the first black President, but in those cases it was a lone nutter rather than a conspiracy.
How long can Trump crash the market before an angry billionaire decides to take him out? The remaining Koch brother is already pouring money into legal challenges against Trump…
There have already been attempts. Maybe the next one will succeed.
Third time’s the charm.
Just because you only know of two doesn’t mean there have only been two.