You think the examples are all before the 60s? There were some very prominent political assassinations during the 60s, Watergate happened during the 70s, etc.
I posted above, but I see no reason to limit things to the USA and I see no reason to limit assassinations to only the successful ones. Just because politicians have better security and actually thwart more assassination attempts, that doesn't mean that the underlying willingness to murder people over politics has gone anywhere.
There are plenty of close calls to show that the schemes were serious: Bolsonaro was stabbed, Reagan was shot, etc.
