the world, the per capita GDP is only about one-seventh that of the United States.

US’s policy and its impact on the economy

The US’s GDP has always being the best in the world. The data shows that from 1980 to 2015, the US accounted for an average of 27.68% of the world’s GDP (the Global economy.com,2016). The United States is one of the world’s largest trading nations, in 2017, the US was the world’s leading importer. After Trump took office, his economic nationalism has moved US trade away from globalization. way from globalisation. The United States recently launched an attack on the WTO and wants to circumvent the WTO dispute settlement mechanism. This is not the first time that Trump has demonstrated protectionism. US trade policy has changed significantly, affecting the US and other countries. There has been no major progress in the three countries’ negotiations on North American Free Trade Agreement (NAFTA). The main controversy is Mexico and Canada’s objections to the US’s proposal that NAFTA needs to include a sunset clause. They also object to the requirement for enjoying the tax free Free Trade Zone that more than 50% of car parts are produced in the US, and 85% are from the three countries. Trump even threatened to terminate NAFTA. The US’s objective is to reduce their trade deficit and the loss of manufacturing jobs. There are some possible risks. First, if the agreement is passed, the international competitiveness of the US auto industry will decline, and the cost of production will increase. Second, if NAFTA is terminated, then the production and employment of the three countries will be affected because their industrial chain is highly integrated after 23 years of deep cooperation. Trump has instigated multiple acts of trade protectionism. On January 23, 2017, Trump formally announced that the United States withdrew from Trans-Pacific Partnership (TPP). The purpose of the Obama administration’s implementation of the TPP was to weaken China’s trade advantage by establishing a regional free trade agreement that would allow the US unrestricted access to the Asia-Pacific market. In fact, while the TPP policy was conducive to consolidating the US’s position in the Asia-Pacific region, it would lead to the outflow of some industries and cause structural unemployment. Trump announced his withdrawal from the TPP as soon as he took office, and added tariffs. The main purpose of his trade policy is “America first” through the promotion of trade protectionism to protect the US labour market, reduce the trade deficit and revive the manufacturing industry. This will protect the development of local businesses and increase jobs. However, there are consequences for withdrawing from the TPP. Trade protectionism is contrary to the globalisation of free trade. If the US implements trade protectionism for a long time, its international influence will be weakened, especially its economic and political influence