Although it’s unlikely he actually said it, it is often claimed that Albert Einstein said that the definition of insanity is doing something over and over again and expecting a different result. By that definition there are a lot of insane people out there discussing mainstream economics.
Take this article, for example. The article tries to argue that Keynesian economics could save the United States. The problem with the article, besides its advocacy of nonsense, is that it’s based on the false premise that the United States government ever stopped following Keynesian economics.
The United States is in the mess that it’s in, in part, because it followed Keynes’ advice instead of Mises’. Instead of relying on free markets, a commodity based currency, and debt avoidance the United States has been relying on cronyism, a fiat currency, and racking up more debt than a drunken teenager with their parents’ credit card. The natural correction mechanisms of markets have been suppressed for decades, which has lead to a massive misallocation of resources. Eventually the problem will become so bad that no force will be able to continue suppressing these market forces and people will get to enjoy the mother of all depressions. Debt, likewise, is unhealthy in the long run because creditors eventually refuse to loan any more money (or buy your debt in the case of the United States) and call in outstanding loans. When those loans are called in and you don’t have the money to pay you end up going bankrupt (or killing your creditors as the United States will likely try to do).
The current United States economy is what you get when a government goes full Keynesian. If you’re really interested in trying to fix this mess you should pick up some books written by Ludwig von Mises and follow their advice.
It is a testament to the power of skilled hand-waving on the one hand, and an infinite capacity for rationalization on the other, that a Keynesian “spend your way to prosperity” scheme could gain any traction whatsoever.