On Friday, continuing to labor under the (now fully debunked) assumption that trade wars are “good” and “easy to win,” Donald Trump announced tariffs on $50 billion of Chinese imports, with the first $34 billion going into effect July 6. Predictably, China announced a plan to retaliate, saying it would “immediately introduce the same scale and equal taxation measures,” and that “all economic and trade achievements reached by the two sides will be invalidated.” At this point, small children across the world could tell you that Beijing will hit back in kind every time the U.S. ratchets up its tariffs. But the current administration, perpetually slow on the uptake, was seemingly surprised by the move. Because on Monday night, by way of payback, President Twitter threatened to impose an additional 10-percent tariff on $200 billion of Chinese imports. And you can probably guess how that went over:

Beijing warned it would retaliate, in a rapid escalation of the trade conflict between the world’s two biggest economies.

In a statement, China’s commerce ministry said the nation will fight back with both “qualitative” and “quantitative” measures if the Trump administration follows through on last night’s threat, saying “such a practice of extreme pressure and blackmailing deviates from the consensus reached by both sides on multiple occasions.” He added: “The United States has initiated a trade war and violated market regulations, and is harming the interests of not just the people of China and the U.S., but of the world.”

The back-and-forth sent global markets sliding, with the S&P 500 falling for a third day straight and the Cboe Volatility Index rising the most in three weeks. “The degree of both rhetoric and substance behind the proposals that have gone back and forth recently is worrisome,” Mark Howard, a senior multi-asset specialist at BNP Paribas, told Bloomberg TV. “This has caused a bit of a risk-off trade today, and it’s a cause of caution by major investors.” The nosedive was so severe, in fact, that it managed to do this:

Of course, China isn’t the only one Trump has pissed off with his economic “policies” as of late. He spent much of late May flipping off the U.S.’s closest economic (and political) allies, going full throttle on his aluminum and steel tariffs, which European Commission President Jean-Claude Juncker called “unjustified,” and to which the E.U. will respond with tariffs of its own on U.S. goods staring in July. Mexico is on its way to imposing $3 billion worth of its own tariffs, and Canada, equally unenthused about Trump’s tactics, responded with duties on $16.6 billion in U.S.-made products. But it’s on the China front that an all-out trade war seems most inevitable. So far, that’s all well and good with Trump’s base, but these happy days could very well come to a screeching halt. “Trump’s biggest crisis will come if the trade wars cause a slowdown in the economy,” one Republican told Axios. “The boom is giving him a cushion against the impact of his policies, personal behavior, and impetuous decision-making. No boom, no cushion. Political collapse.”