The markets haven’t freaked out about the president’s weird contention that he might renege on a portion of the national debt yet. But if he keeps talking about it—watch out.

On Sunday, Trump hinted that the United States might renege on some of the $36.22 trillion that it owes on the national debt. Speaking to reporters Sunday on Air Force One about Elon Musk’s review of government spending, Trump said:

We’re even looking at Treasury. There could be a problem—you’ve been reading about that, with Treasuries, and that could be an interesting problem because it could be that a lot of those things don’t count. In other words, that some of that stuff that we’re finding is very fraudulent, therefore maybe we have less debt than we thought of. Think of that!

“For those not familiar with how financial markets work,” Paul Krugman later explained on BlueSky, “U.S. Treasuries are the ultimate safe asset, used as collateral for everything. Even a hint that some Treasuries might not be honored could bring everything to a screeching halt.”

The bond market’s initial reaction to Trump’s comments was to shrug them off. “Trump’s veiled threat is so insane that it won’t happen,” Harvard economist Jason Furman assured me. Politico’s Victoria Guida quoted an administration official saying that Trump was talking about unspecified Treasury payments, not Treasuries, prompting some of the business press (for instance, Bloomberg) to report that Trump’s meaning was unclear. Trump’s meaning was not unclear, and that administration official was lying when he or she said Trump was talking about unspecified Treasury payments. Go back and look at what Trump said. It’s on video, for Christ’s sake. (Fast forward to 21:15.) He said, “Treasuries.” You aren’t imagining things. Your president is not a well man.

The bond market’s calm won’t last if Trump repeats his threat once or twice more, as he tends to do until he gets a reaction. Or it may react with even greater alarm than expected when Trump and congressional Republicans reveal their deficit-busting tax plan. (The bond market has for some time been freaking out about the budget deficit.) “The political world needs to appreciate the fact that he’s playing with fire that will burn everyone,” MSNBC’s Steve Benen observed Monday. I second that.