According to an article I read recently (I could not find it though), the easiest way to take down a big authority is by cutting the head - meaning the uppermost level of control of that authority - and causing enough chaos to be able to claim that authority yourself.
What if whenever politicians became too shameless in their corruption schemes, someone hired a hitman that eliminates a few important figures, basically sending a message that most of the people are thinking: "We can see what you're doing and we won't just stay and do nothing"? In my very naive opinion, this will send a warning message to any future person occupying that role that they shouldn't fall into corruption schemes or at least not as much. I understand that in today's world the second part - claiming the authority - is complex or impossible, but it's not important. The goal of this is only sending the warning message.
I know that my point of view is very naive, but I'd like to read some ideas about why this won't work.
P.S.: I know this is a global community, so a little background might be helpful - this is coming from someone in Eastern Europe, where life standard is kind of low compared to Western Europe and politicians are more corrupt based on my biased opinion.