Trump made the claim that we must introduce these tariffs on national security grounds, because that is the authority he is using to impose these tariffs, which is an additional slap in the face to our allies.
Trump is probably lying about this, but I've heard the same national security rhetoric used with a straight face by commentators in Australia as a reason to put tariffs on imports, and it's a bad path to go down. Our allies already see us as unreliable now - Germany is considering whether they need nukes now that they can no longer trust us.
And lying about the reasons is basically negotiating in bad faith.
Doesn't Canada put tariffs on the USA? Aren't they also “fucking up relations” with us as well?