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Tariffs are back—or at least the threat of them. Yesterday the Trump administration announced an additional 50 percent import duty on Canadian wine, hockey sticks, and other goods. But the tariffs won’t actually take effect for almost a month, which means they might never: Donald Trump has a history of retreating in exchange for minor concessions. So before you get too worked up, here’s what you need to know.

Wait, I thought the Supreme Court struck down Trump’s tariffs. How is he allowed to do this?

Good memory. The court threw out Trump’s import duties on many foreign products in February, saying he’d overstepped his authority to enact tariffs (which, with rare exceptions, are Congress’ turf). But the latest tariffs on Canada draw on a different presidential power, which permits “new or additional duties” on any country that “discriminates in fact against the commerce of the United States.” No previous president has used that provision to impose tariffs, though, so these may also face legal challenges.

OK, but why is Trump suddenly tariffing Canada again?

The administration says it’s payback for Canadian duties on American cars, dairy products, and alcohol. “Canada has been very, very tough on us over the years,” Trump told reporters today. But the backstory is important: Earlier this month, the administration decided not to renew the U.S.–Mexico–Canada Agreement. (Trump, a legendary flip-flopper, actually negotiated the trade deal in his first term but has since turned against it.) Although the deal remains in force for the next decade, the move could reopen big parts of it to renegotiation. So these latest tariffs may be a bid to jawbone Canada into more favorable terms.

Trump has been pretty aggressive toward Canada. Is there another possible explanation?  

The president has repeatedly (and bizarrely) pledged to annex our northern neighbor as America’s 51^st state, and the timing could reflect presidential pique. Over the weekend, he threatened to punish Canada for wildfires that have blanketed U.S. cities in haze, saying, “Maybe they should pay us some damages or something, or we should do some tariffs.” Today Trump, who has ignored the role of climate change in all of this, denied that the tariffs are about the wildfires; as my colleague Nitish Pahwa explains, he might later slap even more tariffs on Canada. But as the saying goes, where there’s smoke, there’s fire.

If the tariffs do take effect, what would they apply to?

More than 500 Canadian goods are in Trump’s crosshairs, ranging from cheese to cement. In another sign that the tariffs are an effort to force Canada to negotiate, many of the goods in question were shielded from Trump’s earlier duties under the USMCA. But the levies are also relatively limited. They apply to about $20 billion in goods, just 5 percent of what the U.S. imported from Canada last year. Energy, lumber, and other major industries are exempt. And before you get too in the weeds, remember that this might all just be yet another TACO in the making.

Sorry, what’s TACO?

It stands for “Trump Always Chickens Out.” Coined by a Financial Times commentator last year, the term describes Trump’s tendency to rescind his own tariffs—sometimes within days—after the stock market recoils or the targeted countries agree to superficial changes.

If the tariffs are a bluff, how is Canada responding? 

So far, it’s standing firm—while also leaving room to negotiate. Prime Minister Mark Carney criticized the tariffs as a violation of the USMCA. But he also spoke with Trump today and said they’d “agreed to intensify negotiations.” In addition, the U.S. has restarted trade discussions with Mexico, the other country that’s party to the USMCA. Last year, though, Trump repeatedly slapped import duties on both countries. So even if talks continue, these latest tariffs could be just the beginning.

OK, that’s an annoying amount of uncertainty, courtesy of the president. To help you avoid spinning your wheels all night about trade deals, I recommend:

How to fix an out-of-control Supreme Court: One way to stop spiraling about the news is to focus on what you can do about it. Slate’s Jurisprudence team has a new project that offers some hopeful answers about how Americans can reclaim the Constitution—and the law—from nine monarchical justices. Dahlia Lithwick’s stirring opening essay is definitely worth a read.

A treat for trivia fans: Which simple stitch is the basis for all other stitches? Which seafood may be served in a style called Kilpatrick? If you love random facts and want to test your skills, our daily quiz is for you.

(Re)assessing Anne Hathaway: The Odyssey actress has been famous since she was a teenager. She won an Oscar at 30. Yet today she seems perhaps a little underestimated. Isaac Butler (who, fun fact, knew Hathaway in college before her breakout role in The Princess Diaries) reflects on Hathaway’s career, and what we’ve gotten wrong about the star.

Family secrets and sibling drama: A reader is distraught that their siblings threw away their late father’s journals, which held clues about who he really was. Jenée Desmond-Harris offers advice on untangling this knotty disagreement.

Thanks for spending part of your evening with me. Enjoy the rest of your night!