1) I’m not from or in the US

2) political assassination can happen in any country, preventing it is very hard

3) all countries have problems but some have bigger problems than others: https://www.transparency.org/research/cpi/overview

I don't worry much about preventing because you're right, it's close to impossible. more about the lack of investigation. jfk was emblematic because his brother, also a top politician, later was also liked in the same fashion, also with full media coverage and impunity for the responsible parties.