"Use dragons to keep wolves under control, and you eventually have to reward them. And then, they do what they want."
That's the inherent danger of taking the route of the 'lesser evil.' We start with the presumption that it is a small thing, and easily manageable. And if it can rid us of a more pressing, more destructive assailant, we'll be happy to accept it. But feed it for too long, and it too will consume us.
Such is the difficult problem Rome faced in the conflict between Pompey and Julius Caesar. Caesar's eventual defeat of Pompey offered a short reprieve amidst a long series of Civil Wars, after which the Roman people granted Caesar a permanent dictatorship (though he was not yet emperor).
Rome's finest historian, Plutarch, remarks: "However, the Romans bowed their heads before Caesar's good fortune and accepted the bridle. Since autocracy was, from their point of view, a pleasant change after civil war and turmoil, they proclaimed him dictator for life."
But this would have disastrous consequences for Rome. When Caesar was assassinated only four years later, the Romans divided power again, leading to the reignition of the Civil Wars. By the end of them, Rome had been a military state for so long that the Senate had virtually no authority, paving the way for Caesar Augustus to become the functional emperor.
Like all history, drawing a straight line between their time and ours is impossible. But the story of the fall of the Roman Republic (and the rise of the Empire) is a stark reminder of the intrinsic dangers of adopting the lesser of two evils. And for that, it is worth reflecting about.