The point isn't that "the Fed can't do that;" the point is that the Fed cannot create a bid in bidless markets that lasts beyond its own buying. The Fed can buy half the U.S. stock market, all the student loans, all the subprime auto loans, all the defaulted CRE and residential mortgages, and every other worthless asset in America. But that won't create a real bid for any of those assets, once they are revealed as worthless. The nuclear option won't fix anything, because it is fundamentally the wrong tool for the wrong job. Holders of disintegrating assets will be delighted to sell the assets to the Fed, of course, but that won't fix what's fundamentally broken in the American and global economies; it will simply allow the transfer of impaired assets from the financial sector and speculators to the Fed.