What would happen if the US reached its debt ceiling?

The US reaching its debt ceiling becomes more likely these days, and the discussion has already begun. It will add shocks to its politics and economy as well as the financial market and the global economy. I will focus on the economic affects. If the government successfully passes the legislation of raising the debt ceiling, this act could be regarded as another way to default, because the government will then borrow more than it had promised to pay back its debt. The bond yield may then increase and the US dollar may depreciate as well. In addition, this will prevent the Fed from raising the base rate, as the US government wants its loan to be as cheap as possible. It could affect the financial markets in both ways. I believe that the negative force will be stronger at the start, but later the financial market will move back to its original level when it benefits from low interest rates and cheap dollars. If the government fails to pass the legislation, it is highly likely to lead another government shutdown. Government shutdown will significantly damage the economy. It will increase the unemployment rate rapidly, as it directly sends all federal employees home. Although they are very likely to be reemployed, the short term impact on the market will be unexpected. The value of US asset market will continually decrease until the government decides to reopen again.