On July 7 of this year, the official line from President Trump and his allies was that there had been no collusion between his 2016 presidential campaign and Russian interests.

In March, Donald Trump Jr., the president’s son, even told the New York Times that he had never participated in any meetings with Russians related to the campaign.

On July 8, the Times revealed that this wasn’t true: Trump Jr. had met with a Russian attorney named Natalia Veselnitskaya who had links to the Kremlin.

Trump Jr. waved away questions about the meeting. “We primarily discussed a program about the adoption of Russian children that was active and popular with American families years ago and was since ended by the Russian government,” he explained in a statement.

On July 9, the Times revealed that this wasn’t true: Trump Jr. had agreed to the meeting after being promised information that was damaging to Hillary Clinton.

Trump Jr. suggested in a statement that he was told by “an acquaintance” that an individual “might have information helpful to the campaign,” but he wasn’t told her name. During the meeting, though, “it quickly became clear that she had no meaningful information,” and Veselnitskaya then changed topics to adoption.

On July 10, the Times revealed that this wasn’t the whole truth: Trump Jr. had been told in an email that the information being offered was part of an effort by the Russian government to ensure Trump’s election.

“Don Jr.’s takeaway from this communication was that someone had information potentially helpful to the campaign,” a statement from his attorney read, “and it was coming from someone he knew.”

On July 11, Trump Jr. released copies of the emails in an effort to get ahead of another Times story that was about to drop.

His statement upon doing so read, in part: “The information they suggested they had about Hillary Clinton I thought was Political Opposition Research. I first wanted to just have a phone call but when that didn’t work out, they said the woman would be in New York and asked if I would meet. I decided to take the meeting.”

Given the avalanche of increasingly incriminating revelations about this meeting — including that it involved not only Trump Jr. and Veselnitskaya but also campaign chairman Paul Manafort, Jared Kushner and a former Soviet counterintelligence officer named Rinat Akhmetshin — some details were buried in the mix. Among them? That Trump Jr.’s understanding of what information was being presented may indeed have included a phone conversation with a person close to the source.

The emails that originated the meeting came to Trump Jr. from a publicist named Rob Goldstone. One of Goldstone’s clients was a performer named Emin Agalarov, who is also the vice president of a development company in Moscow that partnered with the Trump Organization in 2013 for the Miss Universe pageant in that city.

Goldstone’s emails to Trump Jr. on the subject mentioned Agalarov at the outset.

“Emin just called and asked me to contact you with something very interesting,” he wrote. “The Crown prosecutor of Russia met with his father Aras this morning and in their meeting offered to provide the Trump campaign with some official documents and information that would incriminate Hillary and her dealings with Russia and would be very useful to your father. This is obviously very high level and sensitive information but is part of Russia and it’s government’s support for Mr. Trump — helped along by Aras and Emin.”

Trump Jr., perhaps a bit skeptical, suggests a phone call with Emin the following week before agreeing. Several days later, Goldstone tries to set that up, working to connect Trump Jr. and Agalarov while the latter is performing a concert in Moscow.

It is only after this point that the meeting is set up.

“Emin asked that I schedule a meeting with you and The Russian government attorney who is flying over from Moscow for this Thursday,” Goldstone writes the next day, not using Veselnitskaya’s name (as Trump Jr. Indicated) but clearly indicating her role. “I believe you are aware of the meeting – and so wondered if 3pm or later on Thursday works for you?”

There’s no other communication between Goldstone and Trump Jr. Somehow, between the time when Goldstone and Trump Jr. were trying to set up a call with Agalarov and this email, Agalarov has asked to schedule a meeting with Trump Jr. and Trump Jr. has become aware of that meeting. Trump Jr. had wanted to talk to Emin before a meeting was set up; now, a meeting is being set up.

In an interview with Sean Hannity after the emails were released Trump Jr. was asked if he talked to Emin.

“At any point were you told, either in a phone conversation or otherwise, what they might tell you? What Goldstone seemed to be implying you would receive,” Hannity asks.

“As I recall, it was all basically this email coordination,” Trump Jr. replied. “Let’s try to set up a meeting and see what happens. It’s going to be interesting information. In the end, it wasn’t about that at all.”

On Thursday, Trump Jr. presented testimony to the Senate Judiciary Committee about the meeting and what led up to it. In his prepared statement, he mentioned phone calls with Agalarov.

“My phone records show three very short phone calls between Emin and me between June 6th and 7th,” he said. “I do not recall speaking to Emin. It is possible that we left each other voice mail messages. I simply do not remember.”

An attorney for Agalarov, speaking to The Post, echoed that formulation, saying that his client had “absolutely no memory” of talking to Trump Jr.

That’s a lot of context. Here’s the throughline.

We know that Trump Jr. has proven to be consistently uninterested in offering a full explanation of the events surrounding that meeting until it has become unavoidable for him to do so. We know that perhaps the only record of the phone calls with Agalarov that might exist are records of the calls’ duration, which Trump Jr. has now included in his statement before those records are subpoenaed. We know that Trump Jr. only agreed to the meeting after those calls occurred.

The evidence at hand strongly suggests that Agalarov and Trump Jr. spoke. If they did, that call almost certainly involved Agalarov explaining to Trump Jr. why the meeting was worth his time. Agalarov, to some extent, sold the president’s son on taking the meeting.

How? Why? What was said? It’s not clear. This is why people looking to cover their tracks like to speak in person or over the phone: No paper trail. (Although Agalarov, as a Russian national, certainly may have had his communications surveilled by American intelligence agencies; hence the “perhaps” in the paragraph above.)

Trump Jr. didn’t want people to know about the meeting or, then, the contents of the meeting or, then, the origin of the meeting. Why would we think he’s being forthright about a possible conversation with Agalarov? And why would we then think that he was being forthright about what was said?