For those concerned about the effects of Donald Trump’s trade war, the developments at the G-20 summit offered at least some relief. The American president was prepared to impose a sweeping new round of tariffs on China on Jan. 1, but after talks with President Xi Jinping, both countries agreed to a pause, allowing negotiations to continue.

It was, for all intents and purposes, a temporary cease fire. And yet, Trump quickly hailed the developments as “an incredible deal.”

Indeed, the Republican continued to gush about a trade breakthrough that only he could see. “Farmers will be a a [sic] very BIG and FAST beneficiary of our deal with China,” Trump wrote on Twitter, adding, “China has agreed to reduce and remove tariffs on cars coming into China from the U.S. Currently the tariff is 40%.”

As the New York Times reported, no one seems to have any idea what the American president was talking about.

The disclosure took trade watchers and auto industry figures in both countries by surprise. The issue of auto tariffs had not appeared in either government’s public statement after the trade war truce. Even White House officials who were in the meeting with Mr. Xi were not sure what Mr. Trump meant. Peter Navarro, one of Mr. Trump’s top trade advisers, said on NPR that the subject came up, but he could offer no details. Larry Kudlow, the director of the National Economic Council, acknowledged to reporters in a briefing that he was uncertain what Mr. Trump was referring to but said he hoped all the tariffs will eventually reach zero. “We don’t have a specific agreement on that,” he said.

So when the president announced publicly that China “has agreed to reduce and remove tariffs on cars coming into China from the U.S.,” Trump was either badly confused about a policy he really ought to understand or he was lying.

The “incredible deal” the Republican is so proud of doesn’t appear to exist in reality.

The Times’ report added, “The lack of specific commitments from China and the conflicting statements from United States and Chinese officials struck many analysts as a sign that the president might ultimately get far less than he was publicly portraying.”

Ya think?

At a certain level, I can appreciate why this seems like a dog-bites-man story. “Trump says untrue thing” isn’t exactly a rare headline.

But let’s not lose sight of the significance of the developments: as the planet’s two largest economies engage in a burgeoning trade war, the president of the United States appears publicly confused about the most basic elements of his own policy. Last week, Trump pointed repeatedly to billions of dollars in monthly payments Beijing is paying us, despite the fact that those payments don’t actually exist.

In a Wall Street Journal interview last week, the president managed to effectively get every relevant detail about trade policy wrong. His interview with the Washington Post on the same topic was nearly as bad.

What’s more, as we discussed last week, the problem has been going on for months. The more this president talks about tariffs and trade deficits, the more obvious it becomes that he doesn’t understand what they are. A Washington Post analysis in April explained, “On trade, Trump either doesn’t understand the basic facts or he doesn’t care.”

What should be more embarrassing, the American president appears wholly unaware of his own ignorance. Trump recently boasted, in reference to trade policy, “I understand that issue better than anybody.” Last week, the Republican added, “I know every ingredient. I know every stat. I know it better than anybody knows it.”

It was among the most ridiculous boasts Trump has made since taking office.

Update: On Twitter this morning, the president wrote, in reference to China, “Let the negotiations begin.” Not only did the negotiations begin months ago, but according to Trump two days ago, he already struck “an incredible deal.”