President Trump and Russian President Vladimir Putin shake hands ahead of their meeting in Helsinki on July 16, 2018. (Brendan Smialowski/AFP/Getty Images)

THERE HAS been a welter of news reports, denials, statements and retractions in the past week concerning President Trump’s pursuit of a major real estate deal in Russia during the 2016 campaign, so perhaps some clarification is in order. Here’s what is not in dispute: For most of the time he was running for president, Mr. Trump was also encouraging negotiations that would have put his name on a 100-plus-story tower in Moscow and yielded tens of millions of dollars in revenue for his company. He did this secretly, while publicly defending Russian President Vladi­mir Putin and arguing against sanctions against Russia. And he repeatedly deceived U.S. voters by saying he had no business in the country.

It may not be true, as BuzzFeed reported last week, that the office of special counsel Robert S. Mueller III collected evidence showing that Mr. Trump instructed lawyer Michael Cohen to lie to Congress about the Moscow deal. Mr. Mueller’s office called the report inaccurate. It may be, as Mr. Trump’s counsel Rudolph W. Giuliani said Sunday, that negotiations on the deal continued until the November 2016 election; or maybe, as he said Monday, that timeline was merely “hypothetical.” But we know Mr. Trump thought it perfectly acceptable to clandestinely pursue his personal business interest with the government of a prime U.S. adversary while advancing a presidential platform of improving relations with the regime. Whether that was illegal, it was a profound betrayal of the voters.

Mr. Trump defended his actions last November, after Mr. Cohen confessed to lying about the extent of the negotiations, by saying there was no reason for him to give up “opportunities” such as the proposed Moscow tower because “there was a good chance that I wouldn’t have won” the election. But the record shows it was his presidential candidacy itself that created the opportunity.

Mr. Cohen and another Trump associate, Felix Sater, began working on a plan to license Mr. Trump’s name to a Russian developer after he announced he was running for president in June 2015. Before then, Mr. Sater told BuzzFeed, “a lot of Russians weren’t willing to pay a premium licensing fee to put Donald’s name on their building. Now maybe they would be.”

The two men brokered a deal with a Moscow developer for a tower that was to be the tallest in Europe. Mr. Trump signed the letter of intent the same day as one of the Republican candidate debates, Oct. 28, 2015. According to BuzzFeed’s reporting, the Trump World Tower Moscow was to include a spa created by Ivanka Trump and a penthouse reserved for Mr. Putin.

Mr. Cohen and Mr. Sater continued to work on the deal at least until June 14, 2016, and as Mr. Giuliani confirmed, Mr. Cohen updated Mr. Trump on their progress. One of Mr. Cohen’s aims was to arrange for Mr. Trump to visit Moscow and meet Mr. Putin following the Republican National Convention; presumably both the Trump tower and U.S.-Russian relations would have been on the agenda.

The visit never happened, and Mr. Trump tweeted in late July 2016 that, “for the record, I have ZERO investments in Russia.” Now we know that it wasn’t for lack of trying. Would voters have interpreted the praise he heaped on Mr. Putin differently had they known he was secretly trying to cut his own deal with the regime? The answer seems obvious.