In his Lives of the Twelve Caesars, Suetonius tells us a great deal about the lives (including the sex-lives) of all the emperors from Julius to Domitian. Here is a bit of what he says about the last:

He used to say that the condition of emperors was most wretched, since, whenever a conspiracy had been discovered, no one believed in it unless they [= the emperors] had been killed.

If you want to practice your Latin, here is the original text -- far more concise, as usual with Latin:

Condicionem principum miserrimam aiebat, quibus de coniuratione comperta non crederetur nisi occisis.

In the end, Domitian gave everyone reason to believe him, though not before discovering numerous other conspiracies that he survived. That he thoroughly deserved assassination is an argument for another day.

Some of those complaining that we don't yet have proof that Saddam Hussein is dangerous might want to ponder the implications of this story.