Business and Economics
Source: Economist: 24 Mar 18 "Steel banned"
In 1982, the US put restrictions on cheap steel being imported from Europe. Soon, steel-hungry industries in the US increased imports from non-European nations. End result: steel imports actually increased after the restrictions. Trade is like water, if you try to block its flow in one direction, it merely flows in from somewhere else. Example: under Obama, imports of cheap Chinese steel were restricted. In response, steel imports from nearby Vietnam increased.
More problems with steel tariffs: everyone involved will try and apply for an exemption. It is estimated that the Trump administration will spend 24,000 work-hours evaluating the merits of 4,000 applications for exemptions to the new steel tariff. More importantly, as you can see by the graphic, in the US our steel production sector is far smaller than our steel producing sector. Steel tariffs will harm more workers than they help.