It was a global depression, had many causes, the whole story requires you to look at the whole international system. But policy errors in United States, as well as abroad, did play an important role. And in particular as I said, the Federal Reserve failed in this first challenge in both parts of its mission. It did not use monetary policy aggressively to prevent deflation and the collapse in the economy, so it failed in its economic stability function. And it didn't adequately perform its function as lender of last resort allowing many bank failures and a resulting contraction in credit and also with the money supply. So, in that respect, again, the Fed did not fulfill its intended mission.
Lecture 1: Origins and Mission of the Federal Reserve - The Federal Reserve and the Financial Crisis (2012)