The United States has been accumulating a lot of public debt since the mid-2000s. Studies show that when public debt goes over 90-100% of the country's GDP, it can slow down economic growth. If the debt keeps rising, it could lead to a debt crisis, which usually happens when debt reaches 150-250% of GDP. The U.S. is estimated to hit a crisis point at around 160% of GDP. Right now, the U.S. is feeling some negative effects from its debt, but they're not too severe, and a crisis isn't likely to happen soon.