Then the conversation is completely moot, is it not? Why run a deficit at all or even consider taxing individuals when they can just print all the money they need. Surely it would be less troublesome to just open a state bank and pay interest on deposits than it is to make individuals, corporations, and banks convert their money into bonds to accomplish the same. Why add the extra step? Talking about smoke filled rooms.....
Why does anyone pay taxes if the government can print its own? If the government collects tax for other reasons then what are they? Are they to pick winners and losers?
1) If the government runs deficits that are too large, it will result in inflation. For example, let us say there was full employment. If the government then put in an order for 100 billion in military equipment, the economy would have to "find" labor in order to make that equipment. This would ultimately lead to them "poaching" employment from someone else. That would mean that one segment of the economy would show a loss of productivity while the military side would go up. Production stays the same, but money (demand) goes up. Hence, inflation.
2) So, the government taxes so that it can spend more on essential services. For example, the government may be able to run a trillion dollar deficit without inflation. But they need to spend much more than 1 trillion to fund their projects. They can get that extra spending power and not cause inflation via taxation. Which is why we should want to generally reduce what government does, and let the private sector handle what it can.
3) Private banks are needed so that private banks can expand the money supply in an endogenous, logical, and careful way. We don't want government to be involved in deciding who is creditworthy or not. At the same time, the government likes to put upward pressure on the interest rate. When the government runs deficits, it net adds financial assets to the private sector. These primarily show up on the books of the member banks of the Fed, in the form of assets in their
accounts at the Fed...or, as reserves. Reserves are the currency of the banking system...they can use them to fill reserve requirements (which are paltry), meet cash demand, and as a liquidity hold against their obligations. So when banks increase their obligations (ie, make loans), they like to have a certain amount of reserves to stay "liquid". But, as the government continues to run deficits, the reserves stockpiles get bigger and bigger. At some point, the banks have enough liquidity...and interest rates head toward zero. Knowing that they will always be able to meet their liquidity obligations with no penalties, the cost of money heads towards zero. So, the Federal Government offers debt to the public. When individuals, corporations, and banks buy this debt, they are essentially writing checks to the federal government. To fulfill those checks, the banks have to transfer the reserves back to the government. This drains reserves from the system, and makes the cost of money go upwards. Now, when banks make loans, they have to figure that they'll need to hold more reserves as a liquidity reservoir, and give up on any money they could have gotten from sticking those reserves in a bond.
If it helps you understand this, this is why the Federal Reserve started paying interest on reserve balances. With QE, the banks's reserve balances swelled; the short-term interest rate headed towards zero. The Fed started paying interest on reserves to keep a lower cap on the interest rate.