28万亿美债上限到期，如果这个问题美国无法解决，会发生什么？

Core Viewpoint - The United States is facing an unprecedented debt crisis with a debt ceiling of approximately $28 trillion, which is unsustainable and poses significant challenges for the country's financial future [1][3]. Group 1: Debt Overview - U.S. national debt, referred to as U.S. Treasury securities, is public debt issued by the federal government, categorized into three types: coupon bonds, physical bonds, and book-entry bonds, with varying repayment terms [3]. - Historical growth of U.S. debt has occurred during two significant periods: from $2.6 billion to $26 billion between 1910 and 1920, and from $51 billion to $260 billion between 1940 and 1950, largely due to the impacts of the World Wars [5]. - The reliance on national debt has become a fundamental aspect of U.S. fiscal policy, particularly after the victories in both World Wars, which established the U.S. as a dominant global power [7]. Group 2: Recent Debt Growth - In the 21st century, U.S. debt has expanded significantly, with notable increases during various presidential administrations: from $4.2 trillion to $5.6 trillion under Clinton, $5.6 trillion to $10 trillion under Bush, $10 trillion to $20 trillion under Obama, $20 trillion to $25 trillion under Trump, and surpassing $28 trillion under Biden [10]. - As of April 2021, China holds approximately $1.0923 trillion of U.S. debt, equivalent to about 7.0747 trillion RMB, which is significantly less than the total U.S. debt [12]. Group 3: Debt Management Strategies - The U.S. government has historically managed its debt by rolling over existing debt, a practice known as "borrowing to pay off debt," which has led to a continuous cycle of increasing debt [15]. - The Biden administration continues to issue debt to fund economic stimulus plans, perpetuating a cycle of debt accumulation that poses long-term risks [17]. - Potential solutions to the debt crisis include quantitative easing, which involves increasing the money supply, but this could lead to inflation and devaluation of the dollar, threatening its status as the world's reserve currency [17]. Group 4: International Reactions - Major holders of U.S. debt, such as Japan and China, have begun to reduce their holdings, indicating a shift in international attitudes towards U.S. debt and reflecting changes in the global financial landscape [15]. - Since 2018, China has reduced its U.S. debt holdings by $200 billion, while Japan has also accelerated its reduction, signaling a potential loss of confidence in U.S. fiscal stability [17].