I am reading this article. Therein it is stated that:

Under national security grounds (Section 232), Trump applied tariffs of 25% on steel and 10% on aluminium in March 2018, covering $ 10.2 bn and $ 7.7 bn of US steel and aluminium imports, respectively

The paper further explains:

Section 232 of the Trade Expansion Act of 1962 gives authority to impose or increase tariffs on imports that are thought to threaten national security

It might be due to my complete unfamiliarity with the subject, but I fail to see any connection.

How do Mr. Trump and other adherents of this policy reason that steel Imports threaten national security?

4 Answers 4


By allowing the import of steel, you encourage the dissolution through insolvency of native steel firms (because they often struggle to compete economically with imported steel). This means that you now rely on imported steel for things like tanks and what have you. During times of conflict, there's now the risk that your enemy will cut your supply chains through either use of force or diplomatic pressure and render you incapable of building those machines which are vital for national defence. If you maintain the native capacity to fill those requirements, you are at significantly less risk of being rendered suddenly incapable to build war material.

Note that the other metal targeted here, aluminium, is used heavily in the construction of aircraft and naval vessels.

While I don't know whether this argument was actually advanced by President Trump, it is one that I have heard for considering steel industry as vital to national security.

  • 44
    The problem with this argument, even if it is correct, is that Trump hasn't applied it to the many resources that are even more critical than steel and aluminum. Rare earth metals are just one example. The US no longer even bothers to mine its own rare earths and the people that had the skills and knowledge of how to do it won't be around forever. Aluminum and steel production could be ramped up in a relatively short time if necessary, but how does one start up rare earth mining and production from scratch? Commented Sep 30, 2019 at 13:44
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    There is a wide variety of different steels that differ in composition, properties and price. I doubt that frequently imported and cheap steels, e.g. for the construction industry, are relevant for defense purposes. Sometimes, the public debate about “steel” is being conducted as if it was a simple resource in a computer game, not a complex group of products.
    – lejonet
    Commented Sep 30, 2019 at 18:54
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    @RayButterworth there are good reasons why the national-security argument makes more sense for steel and aluminium than it does for rare earths. The latter are much more low-volume in practice, which makes it easier to store strategic reserves or smuggle around trade blockades. And, they could more realistically be rationed in an emergency. It's hardly possible to build equipment of any use without lots of steel, but rare earths are mostly needed for high-tech high-efficiency. The US could still build decent tanks and save the rare earths for the most critical projects. Commented Oct 1, 2019 at 10:35
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    The same argument can be used to advocate for the nationalisation of the steel industry.
    – gerrit
    Commented Oct 1, 2019 at 11:42
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    Just to be clear, this answer is the justification for the ban given by the US government. It's pretty clear to everyone that banning steel import from Canada, who has been an ally for 200 years isn't because of security concerns. Commented Oct 1, 2019 at 21:31

It's not specifically the import of steel that threatens national security, but rather the loss of domestic steel production capacity. If the U.S. (or any country, for that matter) is relying on most of its steel being imported (especially if it's from less-than-friendly countries,) then your ability to produce things necessary to fight a war can be dramatically curtailed if those steel imports suddenly stop.

Steel is needed to make very nearly everything. Perhaps not quite as much as several decades ago, but it's still pretty high on the list. You can't make cars without it. You can't make tanks without it. You can't make most weapons without it. The list goes on.

This risk is not merely theoretical. Prior to 1940, the U.S. was Japan's primary supplier for oil, steel, iron, and other such high-importance commodities. However, in 1940, as Japan continued its invasion of China, the U.S. began to slow the shipment of those materials to Japan. By mid-1941, once Japan had officially allied itself with Germany and Italy and expanded its invasions of Southeast Asia, the U.S. implemented a full embargo on exports to Japan. The resulting steel and oil (and rubber, etc.) shortages were a MAJOR problem for the Empire of Japan and ultimately contributed heavily to its eventual loss of the war. It was unable to build new ships and aircraft - or to repair or upgrade the ones it had - at anywhere near the U.S. production capacity. For that matter, the same was true for pretty much all of its war material needs. Eventually, it became unable to even fuel what Navy it had left and the Imperial Japanese Navy was rendered more or less useless for the remainder of the war. Once that point was reached, Japan's ultimate surrender was only a matter of time.

Germany tried to force a similar fate on the U.K. during WWII by attempting to disrupt its supply lines from North America. Thankfully, that ultimately didn't work out, as the British and American navies were able to keep the supply lines mostly open.

  • You shouldn't say thankfully, now you're conflating an opinion on what is best. Not everyone agrees with that.
    – paul23
    Commented Oct 2, 2019 at 9:59
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    Of course, this also has another side - the more countries rely on trade with each other, the less capable they are of waging war against one another. If Japan and Germany were self-sufficient before starting the wars, the World War would look quite a bit different - while on the other extreme, if world trade wasn't disrupted beforehand, there would be little reason for conquest in the first place. Of course, neither had much choice either way - they didn't have the resources to be self-sufficient even if they wanted to, and spent loads of effort developing and producing local substitutes.
    – Luaan
    Commented Oct 2, 2019 at 10:22
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    @paul23 I assumed being glad Nazi Germany didn't defeat the U.K. in WWII was a rather uncontroversial opinion these days. To be honest, if someone doesn't agree with that, I'm not sure that I really care about their opinion.
    – reirab
    Commented Oct 2, 2019 at 15:03
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    @Luaan Japan began their conquest of Eastern and Southeast Asia before the disruption of trade. The trade was disrupted because of the conquest (years after it began,) not the other way around. Though it's true that the conquest became more important to Japan after the disruption of trade. You're right about there being two sides to this and the countries relying on each other's exports does help to reduce the probability of war in the first place, though. However, that only works if the dependence is mutual (and, even then, it's not a guarantee.)
    – reirab
    Commented Oct 2, 2019 at 15:07
  • @reirab Yeah, I wasn't thinking about "world <-> Japan" trade in particular; more about the rebirth of protectionism all around the world. Trade wasn't stopped, but there was a large bias towards local production, with many tariffs, monopolies etc. reappearing after a period of relative freedom in trade and foreign investment. Essentialy, you got a positive feedback loop - the more trust disappeared, the more you actually had to rely on local production, and the less you cared about international trade, and all of this of course went hand in hand with nationalism.
    – Luaan
    Commented Oct 3, 2019 at 8:20

"National security" doesn't just mean military security, it also includes economic security, and security of social systems. This effectively gives the President wide latitude in instituting tariffs. As Dan Scally says, it can be justified on the grounds that military equipment depends on steel, and we don't want to be dependent on potential enemies for important munitions.

But the tariffs can also be justified on the grounds of trying to protect the American economy. Making foreign steel more expensive encourages more domestic steel production, which protects American steel companies and the jobs they provide.

The boundary between "national security" and other "national interests" is pretty fuzzy, so the President can use national security as a justification for many policies.

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    Of course, this argument only works if you ignore that the net result is that steel is more expensive. You're "protecting" the economy by moving money from steel consumers to steel producers, while also preventing the worldwide economy from equalizing - all the while countries which didn't tax steel imports benefit from the lower prices. The price for helping the steel producers is the harm to all the other industries, which makes them less competitive. Of course, the usual "solution" is more tarrifs :)
    – Luaan
    Commented Oct 2, 2019 at 10:25
  • @Luaan True, one has to make a number of assumptions about the tradeoffs. Trump's tariff policies are based on serious ignorance (he thinks the tariffs are being paid by the Chinese). I was just trying to provide an additional perspective on the notion of security.
    – Barmar
    Commented Oct 2, 2019 at 16:46
  • By this argument every tariff could be "in the interest of national security". Which would make agreements not to impose tariffs except in the interest of national security irrelevant, since every tariff would be exempt. Commented Oct 2, 2019 at 17:40
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    @DJClayworth I think the point I was suggesting is that the difference between "national security" and "national interest" is quite fuzzy and can potentially be used to justify almost anything.
    – Barmar
    Commented Oct 2, 2019 at 18:08
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    @DJClayworth That doesn't make the answer wrong.
    – Barmar
    Commented Oct 2, 2019 at 18:13

All the above are excellent points and I'd like to add that not only does it take time to build up an industry that has dwindled through reduced use, but there's always technique of the industry personnel who do the work in the mills, the mills themselves get behind in technology because the reduced income doesn't allow for updating/upgrading. Man, there's a ton of reasons metal production is considered strategic.

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    You're getting downvoted because of the unnecessary commentary at the end. Removing that, and adding some sources to back up the point about mills not being upgraded would make this a better answer. Commented Oct 2, 2019 at 22:43

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