USA sanctions ZTE, China counters sorghum... This is the beginning of the Sino-US trade war with the United States to impose a 25% tariff on steel and aluminum products.
 Although USA claims to be the true standard bearer of free trade, its protection of the steel industry is undeniable. Moreover, in fact, USA was protected by import tariffs one and a half centuries ago, and many domestic industries, especially the steel industry, have really developed. Let us start from the beginning. In the 1850s, the vast majority of the manufacturing industry in the USA was still a small workshop. Compared to the United Kingdom, where the industrial revolution originated, the USA steel industry was in a backward stage. In 1860, the output of crude steel in the USA was only 13,000 tons, but by 1900, its annual output of crude steel had exceeded 10 million tons, surpassing the United Kingdom and Germany and becoming a world steel power. How did you do it?
 In 1860, the American Civil War broke out. In terms of foreign economic policy, the southern government at the time supported free trade, while the northern government advocated import duties. At that time, most of the USA steel was imported from the United Kingdom, and the British secretly supported the southern government during the Civil War. Thus, when the North defeated the South, the US government became more hostile to the British, and Congress passed a law on the imposition of import duties on British steel. At the time, USA’s steel king Carnegie sang a big song. He said: “Congress decided to impose a 28% tariff on imported rails... All future concerns about the steel industry are related to the US’s import tariffs. The smoke disappeared." "The people of the USA are determined to establish an independent country. No connected industry can rely on Europe. All forms of steel in the USA and most of the iron needed are once dependent on imports, the British supplier."
 In 1875, British pig iron and crude steel accounted for 47% and 40% of world production, of which 40% of steel exports were shipped to the USA. During the period 1873-1890, the tariff on the United Kingdom for steel products was less than 50%, which directly reduced the competitive pressure faced by the US steel mills at that time. By 1880, according to Carnegie, the value of British industry was 816 million pounds, while the industrial output of the USA had reached 1.126 billion pounds. At this time, although the British Empire still claims to be the day, but in fact, USA has become a world industrial power. At that time, China was rushing into the Westernization Movement, and it will take another 15 years to suffer the heavy losses of the Sino-Japanese War. By the end of the 1890s, the average steel price of the USA had a relatively obvious price advantage over the UK and Germany. The competitiveness of its steel products began to gradually ease the tariff on imported steel. However, after the wind and water turns, 100 years later, the steel industry in Japan, South Korea and China has risen, and the advantage of the steel industry in the USA is no longer. In 1997, more than 30 USA steel companies went bankrupt, and more than 100,000 retired steel workers did not receive health care and insurance benefits.
 Today, the hour hand has been set to 2018. In this era, the advantage of USA is not the industry such as steel and automobile. At this time, the trade protection of the steel industry cannot improve the competitiveness of this industry as it was 150 years ago. It is just a futile struggle.