The US debt has never mattered, because the US dollar is the world reserve currency. That means US debt is the reserves of the world's central banks. If US debt rises, so does the reserves of the world banking system. All central banks were delighted to accumulate more US Treasury debt as it meant the reserves of their banking system went up.

The Federal Reserve can always redeem US Treasury debt by creating money with which to buy it. The debt is always redeemable because it is denominated in dollars.

The problem arrives when the dollar is deserted as world reserve currency. The morons who comprise the Biden regime are scaring central banks away from the dollar as their reserves because of sanctions against Russia, Iran, China, Venezuela, and others. The slow mental processes of central banks are beginning to understand that having your reserves in US Treasury dollar debt means they can be frozen, seized, denied to your use if you cross Washington.

The threat to Washington is, whereas the Fed can print dollars to redeem the debt, the Fed cannot print foreign currencies to redeem the US dollar. So, if central banks shift their reserves out of dollars into gold, as Russia and China are doing, or into other currencies, the supply of dollars in foreign exchange markets have fewer and fewer takers. Consequently the dollar loses its value relative to gold, silver, and rising currencies, and the dollar's value falls in foreign exchange markets. As America's manufacturing is offshored and as America relies on imports of food, US inflation rises. Historically, the Fed's response to inflation has been unemployment.