Doug Casey thinks that assassinating the top people is a good idea.

I think it’s a good idea, frankly, because the miscreants that run governments should be afraid for their own lives and not feel insulated from the bad things they do.

It of course depends on who is meant by top people, and Casey conflates this, since it is long established that punishing your own military, be it by general decimation or execution of unfit commanders, for instance during the 1941 Red Army Purge, inflicts only negligible harm while substantially adding to its discipline.

Of course, if you consider yourself a soldier of God and believe that God is in control of all things, then any military defeat becomes a form of divine discipline, and this doesn't only effect those who consider themselves His soldiers.

The Christian separation of church and state allows both of them to judge as they see fit, because each is setting limits to the execution of the other's judgment: the church can condemn, but not kill, and the state can kill, but not condemn.

These days of course the role of the church has been taken over by the media, but the general separation of judgment still exist.

When people are assassinated, because they are condemned, whether it's Darya Dugin, Brian Thompson or Hassan Nasrallah, the responsibility to kill shifts from the state to those who are ideologically opposed to the assassination the very instant the state representing those opponents stops enforcing its monopoly on killing.

So, assassinations of political leaders make it impossible for their political competitors to rule in the name of the former's supporters, because they can't credibly enforce the states monopoly.

When politicians die under suspicious circumstances like Uwe Barschel or Jürgen Möllemann and nothing happens that is only because they have no real supporters. Basically, what Doug Casey advocates for is the modern equivalent of a witch trial:

Let's assassinate the guy: If that makes his faction stronger and more belligerent, then he was innocent of usurpation, and if it makes it weaker, then he had no legs to stand on in the first place.

By doing this, you'll either strengthen the government or provoke it into exaggerated harshness that is causing dissention, but that mistake is its to make.