The Fed Shouldn't Run Up Its Balance Sheet to Infinity

Milton Friedman once said that the ideal monetary system should always be zero, so cash and bonds would be perfect substitutes. The idea of having lots of short term government debt that we can use to make transactions is just wonderful. So this huge run up in the balance sheet of the Fed doesn't bother you at all. But it bothers me for political reasons because Congress doesn't seem to understand that this is not a kitty that they can go raid.