Donald Trump casually lobbed another serious economic threat at our geopolitical allies over Twitter today.

Based on the Tariffs and Trade Barriers long placed on the U.S. and it great companies and workers by the European Union, if these Tariffs and Barriers are not soon broken down and removed, we will be placing a 20% Tariff on all of their cars coming into the U.S. Build them here! — Donald J. Trump (@realDonaldTrump) June 22, 2018

The tweet was aimed at the German auto industry, and it wasn’t a surprise, exactly. In May, we learned that Trump wanted to place a 25 percent tariff on foreign cars, using the same national security powers that he used to impose border taxes on steel and aluminum imports. As the tweet makes clear, however, our president is not even trying to maintain the legal fiction that these tariffs are actually about national security.

The Trump administration’s great insight about trade policy has been to realize that it can use a relatively obscure Cold War-era law—Section 232 of the Trade Expansion Act of 1962—as an all-purpose permission slip to slap duties on foreign products. The statute empowers the president to raise tariffs in order to defend U.S. “national security” interests—a broadly defined concept that includes the “economic welfare of individual domestic industries” and the “weakening of our internal economy.” If the administration wants to take protectionist measures, in theory it just needs to have the Commerce Department produce a report first purporting to show that imports are undermining our ability to make stuff domestically. That’s all the legal cover Trump needs if he wants to rain down economic revenge on Angela Merkel for looking at him the wrong way.

And yet, Trump keeps giving the game away. After Trump said that he would impose tariffs on steel and aluminum under Section 232, the president announced on Twitter that he would only spare Canada and Mexico from them if they renegotiated NAFTA—thus making it clear that the levies were not about national security or protecting specific industries for the good of the nation at all, but rather gaining negotiating leverage. In the case of cars, the Commerce Department hasn’t even finished its report laying out a national security case yet, and Trump is already admitting that the tariffs are really about battering the EU into making trade concessions.

You’d think that this would all make room for a lawsuit to stop these tariffs, since the president has all but admitted that he’s only using national security as a thin pretense to do whatever the heck he wants. And yet, if its hearing on the administration’s Muslim travel ban are any indication, the Supreme Court appears to be very hesitant to second guess the White House’s official justifications for its actions based on the president’s actual statements. Trump doesn’t care what the law says. And sadly, it seems he doesn’t have to.