I'm not sure what your background is, but I get the sense that you don't really know what you're talking about.

> The reason behind that is actually fairly simple and comes from the sectoral balances, which state that the balances of all sectors in the economy have to add up to zero. So if the non-government sector has a surplus, the government sector must have a deficit, and vice versa.

This is completely false. There have been many instances throughout U.S. history that the U.S. has run surpluses and the economy has boomed. In fact, the better private industry is doing, the lower the deficit should be. That's because more money is being made, and more taxes are collected. If spending maintains a constant level, then the deficit will shrink. The problem is that the government never keeps spending constant. The more money they get, the more they spend. It used to be that deficits were kept in check, though. The difference between the past and present is that now the deficit is larger than it has ever been in U.S. history, by a very wide margin.

> Private actors like to hold monetary assets, i.e. savings, bonds, and so on. This means that somebody else must hold corresponding liabilities.

Again, wrong. There are assets that equal liabilities, such as bonds or accounts receivable. But as a class, assets do not equal liabilities. If I own a factory worth $50 million, then I have equity worth $50 million. Nobody owes me $50 million for my factory.

> The logical way out is for the government sector to provide the required monetary assets, which is only possible via a government deficit.

Ugh. No. IF a government needed to provide monetary assets such as quantitative easing, there is absolutely no requirement to run a deficit to do so. The government can spend out of its surplus budget (if it has one). Again, a deficit means you are spending more than you are taking in. Keep in mind that most countries can't run deficits in perpetuity. If a country like Brazil had a deficit the size of the U.S. they would go bankrupt. It is only because the U.S. dollar is the world's reserve currency that this kind of irresponsibility is allowed for some time.

> Under the current institutional arrangement, an ongoing government deficit means increasing government debt [1]. However, unlike for private actors, there is no sustainability problem for a monetarily sovereign government (this is where your comparison with Greece breaks down - Greece is not monetarily sovereign).

Being monetarily sovereign has nothing to do with it. There are a lot of sovereign countries, Canada, Japan, Korea, that could not run budget deficits in perpetuity. Again, the U.S. is a special case. They hold the world's reserve currency. The moment that changes, then interest rates will spike and inflation will explode. Nobody will want to hold the dollar, so everybody will sell it. That will cause the value to plummet. In fact, the fact that Greece is not monetarily sovereign is precisely why they were able to borrow so much money in the first place. They borrowed from U.S. banks for years. You know why U.S. banks lent to them? Because they hold the same currency as Germany, Italy, and the rest of the EU. If they were still using the Drachma, they couldn't get a loan to buy a used car.

Do you understand that there is no necessary connection between the U.S. printing money and GDP? You seem to believe that somehow the federal government knows how much money to create and this balances perfectly with private industry. That is wrong. The U.S. government, and only the U.S. government can freely print its own money to pay its debts. This has led to an enormous spike in the deficit in the past ten years as politicians have shown no desire to cut spending. They prefer to kick the can down the road. But eventually debts have to be paid. If there is not an unforeseen increase in GDP to pay for the deficit, then it is going to come to a head at some point.