The tariffs will go into effect 15 days from Thursday and will retain flexibility for the president.
Philip Levy, a former trade adviser in President George W. Bush's administration, said the flaw in Trump basing his tariffs on national security was that military allies could ask to be excluded, undermining the president's stated objective of protecting domestic steel and aluminum mill jobs.
"A strong steel and aluminum industry are vital to our national security, absolutely vital", he said.
USA steel production is off from its highs in the 1970s, but the amount of raw steel produced has remained relatively range-bound since 1983.
Railroad tracks run past the blast furnaces of the now-closed Bethlehem Steel mill in Bethlehem, Pennsylvania, April 21, 2016.
Meanwhile, major USA allies hadn't yet been informed as of Thursday morning of final details on the tariff plan, including whether their steel exports will be subject to tariffs.
He further suggested that the president consider: enacting a global tariff of at least 24 percent on all steel imports from all countries; instituting a tariff of at least 53 percent on all steel imports from 12 counties with a quota, or setting a quota on all steel products from all countries equal to 63 percent of 2017 exports to the U.S.
The senior administration official lambasted critics of the president's tariffs saying, "Nobody inside the beltway should express any sort of surprise".
"We are an ally, not a threat", Katainen said.
"So these industries are industries which the president has said we need to be a country, we need to national security, and they are under significant threat". In addition to such iconic brands, the American products that would face a tit-for-tat European Union tariff of 25 percent range from steel bars and motor boats to t-shirts and orange juice, peanut butter and cranberries.
"These measures could make a significant impact on the economic and cooperative relationship between Japan and the United States, who are allies", said Taro Kono, Japan's trade minister, in a statement. The US would also create a process for the exclusion of certain products and for countries with a close security relationship with the US to seek exemptions.
They wrote that adding taxes in the form of tariffs would undermine the economic momentum of the recently passed GOP tax plan.
The tariffs announced today appear to soften what Mr Trump billed last week as a global, "no-exceptions" move to protect the two industries under a 1962 national security trade law.
The Ministry of Commerce said in a statement Friday that China will take "strong measures' to protect its own interests and warned the US government's actions will "seriously shake" the global trade order". "Steel is steel. If you don't have steel, you don't have a country". However, some economists fear that Trump will set off a wave of reprisal tariffs that will eventually damage the steel and aluminium industries in all countries.
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Despite lingering uncertainty about how long the exemption will last, the Mexican peso rose against the United States dollar after the president's announcement and the Canadian dollar also regained ground it had lost against the greenback.
Railing against countries that had "taken advantage" of the United States, Trump accused Germany of behaving unfairly by contributing much less than the USA towards the funding of North Atlantic Treaty Organisation.