When politicians run out of good arguments, their last refuge is often the claim that what they want is “necessary for national defense.” 

Given that there are no economic arguments in favor of tariffs, it makes sense that the administration has resorted to the political “national defense” argument instead. 

So, even if the Trump administration were forced to admit that, yes, tariffs are bad for the incomes and standards of living for most Americans, they could still argue that everyone must make sacrifices for the sake of national security. 

But do these arguments hold any water?

In a Defense Department memo, in response to the President’s tariff proposal, the Secretary of Defense states that the tariffs are not necessary:

… the US military requirements for steel and aluminum each only represent about three percent of US production. Therefore, DoD does not believe that the finds in the reports impact the ability of DoD programs to acquire the steel or aluminum necessary to meet national defense requirements

“The reports” mentioned here are Commerce Department reports pushing for the tariffs. 

The Defense Department memo goes on to advocate for a far more limited tariff than what the Trump administration wants, stating “DoD continues to be concerned about the negative impact on our key allies regarding the recommended options within the reports … targeted tariffs are more preferable than a global quota or global tariff.”

The memo then concludes by noting that if the administration must have steel tariffs, it should at least wait on imposing aluminum tariffs.

Given that it is in the best interests of the Pentagon to overstate the security threats to the United States, the Department’s opposition to the scope and severity of the administration’s tariffs highlight just how truly unnecessary the tariffs are.  

The DoD worries, as it should, that tariffs harm the American relationship with allies, and thus harm American security efforts. 

Even worse, tariffs are harmful to domestic economic strength, which is the real source of both hard and soft American power internationally. 

Implementing policies that are likely to diminish American productivity and competitiveness ultimately poses a direct threat to long term security efforts.