Oh fuck the dual mandate shit. Let us try to get to the basics here.
The Fed controls the money supply. The government says "we need a billion bux". The Treasury, in collusion with the Fed says, "OK US congress, give us 1 billion in tax receipts to buy 1 billion of our treasury notes. And we are going to charge you interest on the money you borrowed from us. And by the way, the one billion in tax receipts you give us were already loaned to you at a certain interest rate."
US government goes yay, we got a billion bux to spend on whatever. Medicare, defense, etc.
So in a few years, when the notes mature, the government gives the treasury their one billion back, but the Fed goes "Hey, where's the interest we charged you on the 1 billion?" The USG goes hamina hamina, and borrows more money in the form of treasuries to pay the interest they now owe, and then go on to borrow more money for government funding in the next round, and the cycle repeats? Do I have that right?