What did Donald Trump do today? 

He imagined, or made up, a trade deal with China he'd made "yesterday."

In recent days, the Trump administration has been carefully backing away from its self-imposed July deadline to, in effect, negotiate hundreds of trade deals simultaneously with the entire world. Not only has Trump failed to make "90 deals in 90 days," even the few "deals" that have been made are small-scale or informal.

No news is good news, in this case: markets have been rising lately on the expectation that Trump will, as his detractors predicted, "chicken out" once again and revert to some relatively low baseline tax on American consumers. This will still cause unnecessary inflation and targeted attacks by foreign governments on American industries, but not to the extent originally feared.

Then today, Trump suddenly declared at an unrelated White House event that he had signed a trade agreement with China. "We just signed with China yesterday," he said, not elaborating.

Nobody—not Trump, not his administration, and not China—had said anything about a "deal" with China on trade yesterday or at any point in the recent past. 

As of this evening, the White House has refused to elaborate on whatever Chinese trade "deal" Trump was imagining.

That said, Trump does seem to have done one deal involving China recently, only as a private citizen. This week, the Trump Organization quietly walked back its claim that the overpriced and underpowered Trump-branded cell phone he's offering will be made in the United States. Or, rather, it changed the language on its website and then denied it had done so.

As pretty much everyone in the tech industry immediately noted when the phone (or a Photoshop of it) was announced, that was impossible, and for the same reason that massively high tariffs on many other foreign products won't work: the highly specialized manufacturing infrastructure needed for it doesn't exist at that scale in the United States. Not only that, it wouldn't make any business sense to spend the billions of dollars necessary to create it when it already exists elsewhere.

The Trump Organization also lowered the already bargain-bin specs on the phone, and pushed back its release date. The phone as described in its promotional materials appears to be a clone of an existing budget Chinese-made phone.

Why does this matter?

• Past a certain point, it doesn't matter if a president is hallucinating or lying when he just makes stuff up. 

• It's wrong to lie to people about making your products in America, even if nobody really believes you at this point. 

• If Trump wants to get into the phone business, he should give up his day job regulating all of his potential competitors in the phone business.