The US national debt has exceeded 34 trillion USD, becoming a major concern for the global economy. The main reasons are high public spending, tax cuts, and low borrowing interest rates for an extended period. The increase in debt puts pressure on the budget, interest rates, and market confidence. In the long term, if not controlled, public debt could weaken the USD, lead to financial crises, and hinder growth. The US Congress needs to find solutions to balance revenue and expenditure to avoid the risk of bad debt and stabilize the economy.