VP Biden mixed the family business with his Ukraine diplomacy.

As soon as Devon Archer’s closed-door sitdown with the House Oversight Committee ended Monday, New York’s Daniel Goldman emerged to give the Democratic spin: President Biden’s conversations with his son’s business partners were innocent discussions about the weather or other niceties. That was exposed as false on Thursday when the committee made the complete transcript public.

Mr. Archer is a former business partner of Hunter Biden and served with him on the board of Ukrainian energy giant Burisma. Mr. Archer described the value-added that Hunter brought to the business as the “brand,” which was the Biden name. When Hunter put his father on speakerphone with his business clients, “there was [a] brand being delivered.”

He further clarified that it was Joe Biden “that brought the most value to the brand.” In other words, Hunter was selling his father’s power in Washington. That is what Burisma was paying for, and it looks like it got its money’s worth. “Burisma would have gone out of business if it didn’t have the brand attached to it,” Mr. Archer said.

Joe Biden famously bragged of his role in using $1 billion in U.S. aid to get Ukrainian prosecutor Viktor Shokin fired during his December 2015 visit to Kyiv. Mr. Archer says Mr. Shokin, who was investigating Burisma, was not “specifically on my radar,” and that he was spun a tale how of Mr. Shokin was actually “good for Burisma.” But he also said he wasn’t on the phone with Hunter, Burisma owner Mykola Zlochevsky and Burisma exec Vadym Pozharski when they “called D.C.” after a meeting in Dubai to discuss how Washington might alleviate the pressure on them.

All of this underscores Joe Biden’s horrendous judgment in blending his son’s business with his duties as Vice President. Mr. Biden was the Obama Administration’s point man for Ukraine, which was fighting Russia’s first invasion, and he can’t claim ignorance about his son’s dealings.

Amos Hochstein, a senior energy official in the Obama Administration, warned the Vice President in 2015 that Russia-backed media were using Hunter’s presence on the Burisma board to “undermine” the U.S. anti-corruption message. The following year a top diplomat in Kyiv, George Kent, was even more blunt in a message to State.

“Ukrainians,” Mr. Kent said, “heard one message from us and then saw another set of behavior, with the family association with a known corrupt figure whose company was known for not playing by the rules in the oil/gas sector.”

Mr. Archer also explained how Hunter received $142,300 from Kazakh oligarch Kenes Rakishev to buy an “expensive car”—either a Fisker or a Porsche. Mr. Rakishev attended a spring 2014 business dinner at Washington’s Cafe Milano with the Vice President and his son. Also in attendance was Elena Baturina, the wife of Moscow’s mayor, who wired $3.5 million to a company linked to Mr. Archer. The House Committee says it will provide more details when it releases its next tranche of related financial documents.

When the public first learned of Hunter’s sleazy deals, Joe Biden denied ever discussing his son’s business with him. But Mr. Archer has also released a letter from Mr. Biden—on official vice presidential stationery—saying how “happy” he was that Mr. Archer was in business with his son. The letter was written right after a lunch he and Mr. Archer attended with visiting Chinese President Hu Jintao.

It’s one thing to develop relationships in office that turn into business opportunities later, the way Jared Kushner, Donald Trump’s son-in-law, did in the Middle East. It’s another to leverage the office while in office to promote the family business. As Mr. Archer said, the advantage of the Biden brand is that legally “people would be intimidated to mess with them.”

Whether or not Joe Biden took a dime from these dealings, this is a form of political corruption. Covered up by the press in 2020, it will be an issue in 2024. Democrats should worry that as more facts emerge about the Biden mix of politics and business, it could help Mr. Trump neutralize his many legal vulnerabilities.