The import tariffs on steel and aluminum imposed by the USA in 2018 were illegal according to the verdict of dispute arbitrators at the World Trade Organization (WTO).
According to the judgment published on Friday evening, the government of then President Donald Trump violated WTO requirements.
Plaintiffs were China, Norway, Switzerland and Turkey.
The EU had also initially filed a lawsuit against the USA at the WTO because of the tariffs, but then let the case rest.
At the time, the United States had imposed tariffs of up to 25 percent.
They justified this by saying that imports threatened the country's national security.
Because under the rules of the WTO and its predecessor, the GATT, countries have the right to suspend trade concessions such as duty-free imports without further justification in order to protect their national security, the US government took the view that the WTO dispute settlement should not deal with the issue at all .
The judges rejected that.
It must be examined objectively whether a government's reasons for imposing measures to protect national security are covered by WTO rules.
This was not the case.
Countries that win WTO dispute settlement are entitled to compensation to the extent that they have been harmed by an objected measure.
However, the US can formally appeal.
However, because Washington has been blocking the appointment of new appointments to the Appellate Body for years, appointment negotiations cannot take place at the moment.
The case then remains unsolved.