> Hypothetically speaking, how hard would it be to kill someone like this?

I've always found it strange that what happened to Abe recently hasn't happened to just about every world leader, most of whom do public events on a daily basis. In most countries with 50% opposing you, you've got an average of about 20 million people. Take the top 0.01% craziest fanatical opposition and you've still got 2000 people. In the US for example, there are 400 million firearms and god knows how many political lunatics, yet only one president was assassinated in the last century.

Not that it's a good idea.