Right, lots of people do not understand our system. The TREASURY determines how much and which types of treasuries are sold on the open market, NOT THE FED. How does the Treasury decide how much to sell? Easy, they are charged with keeping the federal government running. There's a budget, there's how much has been spent, there's how much has been taken in with taxes, and the difference is the amount the Treasury MUST sell to keep the lights on. The Fed simply decides how much and which types of treasuries it wants to buy to carry out its mandate of price stability and maximal sustainable employment and that process of buying treasuries turns it into public debt. The Fed can also control the money supply by buying treasuries (adding to the money supply) or it can sell treasuries (decreasing the money supply). If the Fed does not buy these treasuries with our money, other people, organizations, and countries buy them. CONGRESS and to a lesser degree the Executive spends the money and they are responsible for the deficit that the Treasury then MUST close by selling Treasuries.
Our problem is we spend too much relative to how much we collect, we collect too little relative to how much we spend, and we have turned most of this mismatch into public debt. We are too focused on the turning into public debt part, which would be unnecessary if we could get spending and taxation right, and IMO all three of these need to be attacked, aggressively, and both sides of the aisle have been failing us for decades. I'm not hopeful looking forward, regardless of who wins which election.