Nowadays Machiavelli's name is primarily associated with a crudely selfish set of ethics, and his book The Prince isn't read very much.
If people actually did read the book they might be surprised to find that what Machiavelli offered was an alternative to the prevailing political ideas of the time, which essentially called for rulers to adhere to certain classical values, in the hope that fortune would smile upon them for abstract and essentially superstitious reasons.
Machiavelli pointed out that the correct way to govern is to study the actual effects of policies and actions that the ruler undertakes, and make decisions based on the likely results of those policies. We style this as "the ends justify the means" but the phrase would probably be easier to grasp in a slightly less loaded form, like "consider the results to determine the policy."
Despite Machiavelli's blackened reputation, he won the argument. For the most part we no longer govern by trying to project classical values like steadfastness, honesty, or loyalty. Yet when the topic is macroeconomics all too often these old ideas seem to seep in.
Krugman today points out a recent case: economists' belief that Great Britain's "austerity" would inspire "confidence" in business leaders, leading to robust private sector investment and growth. It didn't work! Apparently business leaders aren't impressed by 14th-century European political superstitions masquerading as sound finance policy.
There is absolutely no operational reason to believe that decreasing the amount of money flowing from the public sector to the private sector should increase business confidence. The only explanation for this widespread misconception is the belief that "austerity" is a sign of "seriousness" and "prudence" and other wonderful classical values that, if our leaders can merely project them strongly enough, will cause fortune to smile upon our humble economy.
This is no way to run a country, be it on this side of the Atlantic or the other. Public deficits are contributing to increased savings rates, which are in turn improving the creditworthiness of potential borrowers and leading banks to lend to the public. Cutting those deficits will cut savings rates, and before long dissavings will cause people to exhaust their ability to borrow and we'll be right back where we started.
That sounds pretty austere, all right. But it doesn't sound like good policy.