Trump just lost his global tariff sword. Will his boasts of being the ‘world’s greatest dealmaker’ now be put to the test?

The Supreme Court’s decision to gut President Donald Trump’s ability to impose unlimited tariffs on imports from any country will force him to revert to a traditional set of diplomatic tools that he has largely ignored since returning to power.

The Friday decision, which came after months of speculation on whether the high court would permit him to continue claiming sweeping taxation powers under a 1977 law — the International Emergency Economic Powers Act, which had never before been used for that purpose — struck down nearly every tariff Trump has levied on imports from most American trading partners since returning to the White House last January.

Gone are the “Liberation Day” tariffs he has touted as one of his major accomplishments since rolling out his “reciprocal tariff” policy at a shambolic Rose Garden event last April at which he displayed a poster showing he was putting taxes on imports from the uninhabited Heard and McDonald islands near Antarctica among other places.

Also struck from the books are the taxes he has placed, raised and lowered on a whim upon imports from China, Mexico and Canada — three of America’s largest trading partners — using a spurious justification based on the need to force them to crack down on fentanyl smuggling into the U.S.

Now, he’ll have to engage in real negotiations — not bullying — and treat trading partners as peers instead of vassals. In short, the man who White House officials routinely call the “dealmaker-in-chief” — and who for decades has called himself the "world's greatest dealmaker” — will actually need to get down to the hard work of making real deals.

And aficionados of Swiss timepieces can rejoice now that the court has invalidated the 15 percent tax on imports from Switzerland he imposed after Rolex executives and other Swiss watchmakers brought him a solid gold bar and a desk clock to convince him to cut a 39 percent tax he’d announced after he was displeased by a phone call from a female Swiss official.

It was that sequence of events with Switzerland that perhaps best illustrates how Trump had used his now-eviscerated authority to bully and cajole world leaders while occasionally extracting concessions (and gifts of precious metal) from them as part of his quixotic mission to roll back decades of globalization and supply chain integration.

He has used the invalidated powers as a sort of Swiss Army knife, his answer to any and all global problems.

India and Pakistan are fighting? Threaten tariffs and claim credit when the two nuclear powers act like nuclear powers by backing off before a skirmish turns into a war.

Want to pad pharmaceutical companies profits while browbeating them into following de facto price controls that have no basis in American law? Threaten to tax imports from countries with single-payer health systems unless they agree to pay higher prices than the ones that they’ve negotiated.

Angry because Denmark doesn’t want to cede control of a landmass it has counted as a colony or territory for more than three centuries? Feeling emasculated because other NATO allies have sent troops to that territory after you threatened to invade it? More tariffs, of course!

Concerned because farmers who voted for you are reeling after China retaliated against your tariffs by cutting purchases of their crops? Use the tariffs — or at least the revenue collected from them.

It really didn’t matter what the problem was. For the last 13 months, tariffs have been Donald Trump’s solution — even though they are taxes paid by American importers which multiple analyses, including one recent study by the New York Federal Reserve, have shown to be getting in the way of his own efforts to address stubborn cost-of-living issues.

Trump claims the same Supreme Court ruling which eviscerated his use of IEEPA for tariffs left him with even stronger powers to impose even higher tariffs.

To some extent, that’s true. One authority he invoked today allows him to impose up to 15 percent taxes on all imports for up to 150 days (or more if Congress agrees).

Others would allow him to reimpose some levies but only after investigations, justifications, and time-consuming legal processes that can be challenged in court.

But from today forward, Trump’s ability to threaten a country’s exports on a whim has been more or less wiped away.