Can the Federal Government Go Bankrupt?

The private sector competes like crazy. They love to hold government, federal government debt, us. Treasury bonds and notes. Why? Because it is a risk free investment and you can earn interest. But how can i say the federal government debt us are safe? What if the government goes bankrupt? That would certainly be a problem. How does a business go bankrupt? Businesses go bankrupt when they they have so many expenses and army income that they don't maay money. Can the federal government run out of money? It can't because the federal government has a monopoly over the currency. By spending it's impossible for the federal government to go bankrupt unless politicians choose to.