美债“雪球”为何越滚越大？（环球热点）

Core Viewpoint - The U.S. federal government has ended the longest shutdown in history, lasting 43 days, but the situation has exacerbated the already critical federal debt, which has surpassed $38 trillion, raising concerns about fiscal sustainability and the current federal policies [1][2]. Group 1: Reasons for Rising U.S. National Debt - The rapid increase in U.S. national debt is attributed to two main factors: a large existing debt stock and high new deficits, leading to a "snowball effect" where new debt is issued to pay off old debt [2][4]. - Structural spending growth, particularly in social security and healthcare, coupled with slow growth in fiscal revenue, has created a mismatch between spending and income, resulting in a deficit structure [4][5]. - The rising cost of debt due to multiple interest rate hikes by the Federal Reserve to combat economic slowdown and inflation has further expanded the debt scale [4][5]. Group 2: Consequences of High National Debt - In the short term, high national debt will lead to sustained inflation, a loss of the highest credit rating for U.S. Treasury bonds, and increased volatility in bond yields [7][8]. - Long-term effects include erosion of budgetary space for the government, reduced fiscal flexibility during economic downturns, and increased borrowing costs due to rising risk premiums [9][10]. - The societal impact includes intergenerational debt transfer, where the current generation's debt burden will fall on future generations [9][10]. Group 3: Policy Responses and Challenges - The U.S. government has limited policy tools to address the rising debt, with current strategies focusing on increasing revenue through tariffs and reducing spending, but these measures face significant political resistance [10][12]. - Structural reforms are necessary to address the underlying issues of debt, including tax reforms and adjustments to high-spending programs like healthcare and social security [13]. - Achieving a bipartisan consensus on long-term fiscal responsibility remains a significant challenge due to increasing political polarization [13].