In the wake of North Korea’s test of its most powerful nuclear bomb yet on Sunday, President Donald Trump has made another vague, ominous threat on Twitter.

But this time, it’s about economics rather than “fire and fury”:

The United States is considering, in addition to other options, stopping all trade with any country doing business with North Korea. — Donald J. Trump (@realDonaldTrump) September 3, 2017

This threat to stop all trade with countries doing business with North Korea seems to be directed at China. North Korea relies on China for about 90 percent of its foreign trade, as my colleague Zeeshan Aleem recently wrote. Furthermore, Trump has repeatedly complained that China hasn’t done enough to “help” with the North Korea problem.

But the threat that the US would stop “all trade” with China seems laughably implausible. The US and China engage in hundreds of billions of dollars’ worth of trade each year, and “stopping” this would cause massive turmoil in the US economy (as well as, of course, in the global economy).

Perhaps unsurprisingly, Treasury Secretary Steve Mnuchin used an appearance on Fox News Sunday to frame the proposal in terms of working with China to toughen sanctions on the Kim regime, and not in terms of trying to punish Beijing.

“I’m going to draft a sanctions package to send to the president for his strong consideration, that anybody that wants to do trade or business with them would be prevented from doing trade or business with us,” Mnuchin said. But he added right afterward: “We are going to work with our allies. We’ll work with China.”

Mnuchin continued: “We work with China and others. China has a lot of trade with them. There’s a lot we can do to cut them off economically, much more than we’ve done already.”

So despite the president’s sweeping language, what is probably more likely to materialize in the end is some marginal toughening of existing sanctions, sold with tough talk. If true, that would reveal Trump’s rhetoric to be rather empty, but it would be a better outcome than a trade war.