Trump was just undercut by the Pentagon on his shocking claim of a Saudi Arabia quid pro quo

Donald Trump is the most explicitly transactional of modern presidents, and it's gotten him into trouble. His offering of support from the U.S. government to Ukraine in exchange for a personal favor — an announcement of investigations into his political rivals — wound up making him the third American president to be impeached.

And in an interview with Fox News' Laura Ingraham last Friday, Trump revealed he was engaging in another explicit quid pro quo — not, apparently, for a personal favor, but corrupting nonetheless — with Saudi Arabia.

"We're sending more [troops] to Saudi Arabia, and Saudi Arabia is paying us for it," Trump said. "I said 'Listen, you're a very rich country. You want more troops? I'm going to send them to you. But you've got to pay us.'"

This is pretty much as direct a quid pro quo as you can get — an offer to do something on the condition of getting paid. And since what is supposedly being paid for is U.S. military personnel, critics argued that Trump was turning American forces into a de facto mercenary army.

"He sells troops," said Rep. Justin Amash (I-MN) on Twitter.

Trump even went further with his claim, saying the payment was already sent to "the bank," though he didn't specify which bank, and Ingraham didn't press him.

"They're paying us," Trump said. "They've already deposited $1 billion in the bank."

According to a statement from the Pentagon to Vox, however, none of this is right.

It said the Defense Department "has engaged Saudi Arabia on contributing to US activities that support regional security and dissuade hostility and aggression," and that the country had agreed. However, it doesn't look like any money has actually changed hands, as the Pentagon said that "discussions are ongoing to formalize these contributions."

The Pentagon also pushed back on the quid pro quo Trump laid out, without calling him out directly.

"Contributions of this nature do not lead to the deployment of additional US forces, and they do not drive DoD to take on new missions or responsibilities," it said.

What's left unknown is who is really telling the truth. Trump lies all the time, of course, but sometimes he has accidental bouts of candor. And administration officials often shade the truth, or contradict the known facts entirely, in an effort to avoid the horrifying implications of Trump's claims. Regardless, Trump seems to want people to think the U.S. military is up for sale, which is terrifying enough on its own.