“This makes plain that it’s not about national security and it never was about national security,” says Clark Packard, a trade policy analyst for the R Street Institute, a free market think tank in Washington, D.C.
This is more than a rhetorical point. Without the “national security” argument, Trump’s authority to unilaterally impose tariffs on Canadian steel and aluminum is called into question. It doesn’t mean Trump will back down, says Packard, but the tweet could create leverage for other entities—Congress, the courts, perhaps the World Trade Organization—to challenge them.
“Yeah, I think that’s certainly possible,” says Packard. “I hope so.”