President Donald Trump imposed tariffs on steel and aluminum at a press conference at the White House today, but decided to exempt Canada and Mexico during NAFTA negotiations.

Flanked by aluminum and steel workers, Trump signed two proclamations: a 25% tariff on steel imports and a 10% tariff on aluminum imports. These tariffs go into effect in 15 days.

He chose to exempt Mexico and Canada as we continue our NAFTA negotiations with those leaders.

Trump also said he would remain very flexible on tariffs. He noted Australia “as an example of a country whose trade and security relationship with the U.S. may earn an exemption from the punishing tariffs.”

Trump declared that he has the right the raise or lower the tariffs as he sees fit while also owning the right to add or remove countries from the tariffs:

“We have to protect and build our steel and aluminum industries,” Trump said during a signing ceremony at the White House.

“This is not merely an economic disaster, but it’s a security disaster,” Trump said. “We want to build our ships, we want to build our planes, we want to build our military equipment with steel, with aluminum, from our country.”

He stated that America “just wants fairness.”

His speech encouraged foreign producers of steel and aluminum to move to America in order to avoid the tariffs. He reminded them that the GOP’s tax legislation “would also benefit their business if they invested in the U.S.”

The U.S. imports more steel than any other country in the world and four times more than it exports. We “imported five times as much primary aluminum” than we produced in 2016.

Trump did all of this despite the mass criticism he has received from his own party.

Outgoing Arizona Senator Jeff Flake (R) has threatened to put forth a bill that would nullify these tariffs:

“I’m going to — as soon as it comes out if it is anything approximating what he’s talked about — introduce legislation to nullify it. I’m assuming I won’t be the only one to do that,” the frequent Trump critic told reporters Thursday.

Flake, like many Republicans, has expressed deep concerns about Trump’s plans to issue new tariffs on aluminum and steel and says he’s ready to fight legislatively if needed.