From Ryan Avent via Sumner:
The Fed has the ability to create as much money as it wants and can use that money to purchase every scrap of federal-government debt, every scrap of outstanding mortgage-backed securities backed by federal housing agencies, and as much foreign exchange as other governments will sell it.
Sure. And that would do absolutely nothing to remove debt (payment obligations) from the economy.
The problem is not that we have debt-as-assets (income sources). The problem is that there was so much debt-as-liability (payment obligations) that debt-as-assets became "toxic" (undependable income).
Rather than the Fed printing money and using it to buy up debt-as-assets, they should print money and use it to pay off debt-as-liability. This would destroy the liability and free up the economy to grow again.
The other thing, buying debt-as-assets, puts more money into the hands of people who already have more money than they need, and does nothing about the problem that brought the economy to its knees.