When Niccolo Machiavelli died in 1527, Washington, DC was still more than two and a half centuries away from being founded. But he understood perfectly how that dismal city would work, as Bertrand Russell reminds:
“In the absence of any guiding principle, politics becomes a naked struggle for power; The Prince give shrewd advice as to how to play this game successfully.”
-Bertrand Russell, History of Western Philosophy, xxii-xxiii.
Machiavelli was, in many ways, the first modern public choice theorist. Had he lived in a post-Adam Smith world, he would have made a fine economist. A politician’s guiding principle is usually not ideology. It is to remain in power. So they behave accordingly. The first lesson of economics is that people respond to incentives. If someone’s incentive is to get re-elected, they will behave in a way conducive to achieving that goal. Morality and the greater good compete for a distant second.