All eyes are on the Supreme Court as it hears arguments on President Trump’s global tariffs. The case will not only decide the fate of one of the president’s signature policies but will also carry far broader implications for presidential power over international trade and even climate policy.

If the Supreme Court rules for Trump, it will enable a future president to use tariffs to advance a wide range of domestic policy goals. Among other things, such a power would likely enable a president to unilaterally adopt a longstanding policy priority of the climate movement: a tariff on imported carbon-intensive products known as a carbon border adjustment.

The case Learning Resources, Inc. v. Trump asks whether the his tariffs are legal under the International Emergency Economic Powers Act. Congress passed the act in the late 1970s to empower presidents to use economic sanctions to address “unusual and extraordinary” national emergencies.

For nearly half a century, this power was used sparingly to impose targeted economic sanctions in response to discrete foreign threats, like prohibiting transactions with the Taliban and restricting enriched uranium.

That all changed after Trump returned to office this year. In April, Trump declared........

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