President Trump’s legal team offered a number of strained defenses over the course of the impeachment trial. But even as he celebrated his acquittal in a lengthy White House monologue Thursday, Trump conjured a new one.

He said not only that he didn’t do anything wrong but that he had to bring up to Ukraine the allegations regarding Joe Biden and his son Hunter.

Trump pointed to a legal cooperation treaty between the United States and Ukraine that was signed in 1998 and went into effect in 2001.

“We even have a treaty — 2001, 1999 — it’s a treaty, signed treaty, that we will work together to root out corruption in Ukraine,” Trump said. “I probably have a legal obligation, Mr. Attorney [General], to report corruption.”

The problem with Trump’s claim is that there is nothing in the treaty that compels him to report alleged corruption to Ukraine. It’s mostly about what forms of assistance each country should provide to the other when there are legal matters that span both countries. There is no mention of “corruption” in it, and in fact, if Trump was acting according to the treaty, he wasn’t abiding by it.

The treaty specifies that any forms of cooperation must be run through the country’s top prosecutors — in the case of the United States, the attorney general.

“Each Contracting State shall have a Central Authority to make and receive requests pursuant to this Treaty,” it says. “For the United States of America, the Central Authority shall be the Attorney General or a person designated by the Attorney General.”

The Justice Department has said explicitly that it wasn’t involved in Rudolph W. Giuliani’s efforts to get Ukraine to launch the president’s required investigations. And in fact, it has strained to distance itself from Trump’s personal attorney. To the extent this did involve actual government officials, they were diplomats from the State Department — Gordon Sondland and Kurt Volker — and then-Energy Secretary Rick Perry, not lawyers from the Justice Department, as the treaty states.

What’s more, even if the treaty did require Trump to report potential corruption inside Ukraine, there appears to be an exception that would pertain to the Bidens.

“The Central Authority of the Requested State may deny assistance if … the request relates to a political offense,” the treaty says. In other words, the treaty seemed to try to prevent these matters from being politically weaponized.

In fact, the only section in which the treaty refers to informing the other country about potential wrongdoing is when it states plainly that it’s an option — rather than an obligation.

“If the Central Authority of one Contracting State becomes aware of proceeds or instrumentalities of offenses that are located in the other State and may be forfeitable or otherwise subject to seizure under the laws of that State, it may so inform the Central Authority of the other State,” the treaty says.

It seems there is a very good reason this treaty never came up in the hours and hours of defenses that Trump’s legal team offered.

But even setting that aside, the fact that Trump is still explaining his actions suggests he’s not nearly as chastened as GOP senators predicted and/or hoped he would be.