One former official in President Trump’s administration was explicit when speaking with The Washington Post’s Shane Harris, Josh Dawsey and Carol D. Leonnig.

Asked why he believed Ukraine was the country responsible for interfering in the 2016 election, the official said that Trump answered directly: “Putin told me” — referring to Russian President Vladimir Putin.

It’s not clear when that is alleged to have happened, precisely. Trump had been publicly questioning Russia’s involvement in the hacking of the Democratic National Committee for months by the time he was president, claiming on multiple occasions that perhaps it was another country that had access the DNC’s network early in 2016. Maybe, he said in a general-election debate, it was China or “lots of other people” who hacked the DNC.

After he won, a similar refrain.

“I don’t want anyone hacking us. And I’m not only talking about countries. I’m talking about anyone, period,” he said that December. “But if you’re going to do that, I think you should not just say Russia; you should say other countries also, and maybe other individuals.”

That was on Dec. 11, 2016. Two days before, news of Russia’s attempt to interfere in the election had been made public. And four weeks before, Trump had had his first phone conversation with Putin as president-elect.

Several different threads intertwined between the 2016 election and the point at which House Democrats launched an impeachment inquiry into Trump’s interactions with Ukraine. In one thread, Trump repeatedly talked about Ukraine in news conferences and speeches. In another thread, there were his interactions with the Russian president, a total of 20 phone calls or one-on-one meetings from the day he won the election until this July. In two other threads, the conspiracy theories Trump would ultimately raise with Ukrainian President Volodymyr Zelensky emerged into the public.

One focused on former vice president Joe Biden. The other, on this unfounded idea that Ukraine had interfered to oppose his election.

Trump first spoke regularly about Ukraine when the Republican Party was still conducting its 2016 primary. Part of his standard patter was that the United States and then-President Barack Obama were handling foreign policy poorly. Ukraine became an example of that, a demonstration of how other countries (Germany and NATO in particular) were allowed to skate while the United States carried most of the weight in defending Ukraine against Russian aggression.

Once he took office, though, his mentions of Ukraine became regular, generally offered in the context of his relationship with Putin. (Those anodyne mentions of Ukraine are the small dots on the red timeline above.) Putin and he needed to talk about Ukraine (and Syria and terrorism) or he and Putin had spoken about Ukraine and that’s why it was important to have a strong relationship with the Russian leader. All of this was in the context of that December report about Russian interference, which soon blossomed into a public investigation of the Trump campaign’s possible complicity in the effort. His relationship with Putin was being questioned, and Trump generally responded by arguing that he and his counterpart needed to discuss Ukraine.

He and Putin spoke regularly. Over the course of 2017, he and Putin had six phone calls and three in-person meetings (the light-colored dots on the orange line above). The first two meetings occurred in July, at a Group of 20 summit in Germany. Trump and Putin held a bilateral meeting, after which Trump famously confiscated the American staffer’s notes. Later the same day, he and Putin had an informal conversation at a dinner, at which no other Americans were present.

On the way home from this meeting, he learned that the New York Times was prepared to report that members of his campaign, including Donald Trump Jr., had met with a Kremlin-linked attorney at Trump Tower in June 2016. He crafted a response for his son focused on the issue of adoptions — something he later said that he and Putin had discussed in their one-on-one conversation.

By that point, Trump had already publicly raised the idea that Ukraine was somehow involved in the DNC hack. That hack began in April 2016 and was attributed to Russia by the American firm CrowdStrike in June of that year. A report issued by CrowdStrike in December became the focus of criticism in early 2017, with Breitbart, among others, criticizing the conclusions. (The author of one critical article now works for the Russian government-funded Sputnik news agency.) That turned into an odd conspiracy theory linking, through several degrees of loose separation, a CrowdStrike co-founder to a Ukrainian oligarch named Victor Pinchuk.

The theory onto which Trump latched was that this showed a Ukrainian hand in blaming Russia for the DNC hack, a claim which, if true, might help dissipate the Russia “cloud” (as Trump called it) that was then hanging over his head. The irony to this claim, though, was that Trump himself was linked to Pinchuk, having participated by teleconference in an event that Pinchuk was moderating. According to the Times, Pinchuk also covered Trump’s fee.

“I know many people that live in the Ukraine,” Trump said during that appearance in September 2015. “They’re friends of mine. They’re fantastic people. Victor is an example.”

In interviews focused on his 100th day in office, Trump was elevating the Ukraine-DNC theory.

“Nobody asks John Podesta why he didn’t let the FBI look at his server, why did they hire another company to look at the server,” Trump told the Washington Examiner, confusing Hillary Clinton’s campaign chairman, Podesta, with the DNC. “And somebody had mentioned — and this may be incorrect — a company that’s owned by somebody from the Ukraine. You’ve heard that, I assume you’ve heard that?”

That interview was on April 26, 2017. Trump and Putin had spoken on April 3, following a terrorist attack in St. Petersburg — the third time the two had spoken, since Trump was a candidate. (He and Putin had communicated indirectly in 2013 when the Miss Universe pageant, then owned by Trump, held an event in Moscow.)

From then on, the Ukraine-DNC theory was integrated into Trump’s worldview. It only popped up sporadically until this year, as when he mentioned the idea indirectly in August 2017, during a news conference in which he also defended his former campaign chairman Paul Manafort.

“The Democrats colluded on the Ukraine,” Trump said. “So they colluded. And then when you get down to it, why isn’t the FBI looking at the DNC server? You have a server that they refuse — the Democrats refuse to give to the FBI.”

This thing about the server isn’t accurate, but the point is the connection: Talking about Ukraine, Trump transitions into his theories about the DNC hacking. Trump and Putin had met the previous month in Germany, but it’s worth also noting the Manafort part of the news conference. Some have also suggested that Trump’s theories on Ukrainian culpability in 2016 may come from Manafort, who has connections to Russia through his work in Ukraine for a pro-Russian political party and who was ousted from Trump’s campaign after a Ukrainian politician publicized documents suggesting illicit payments to Manafort.

Trump’s most famous meeting with Putin occurred in July 2018, during a point at which his Ukraine theories had lulled.

Asked by The Post’s Philip Rucker if he would confront Putin about Russia’s 2016 interference during their one-on-one, Trump responded curtly.

“We will, of course, ask your favorite question about meddling,” he said. “I will be asking that question again. But we’ll also be talking about other things. We’ll be talking about Ukraine.”

A year ago, the issue of Ukraine reemerged as prominent when Trump’s personal attorney Rudolph W. Giuliani began speaking with Ukraine’s former prosecutor general about Biden. That former prosecutor, Viktor Shokin, was fired in early 2016 after broad criticism for having not aggressively targeted corruption. Biden helped push for his ouster, no doubt earning him Shokin’s enmity. Shokin claims that Biden was trying to protect his son Hunter, who served on the board of a Ukrainian energy company, but there’s no reliable evidence that’s the case.

Giuliani spoke with Shokin and then-Prosecutor General Yuri Lutsenko in late 2018 and into early 2019. Eventually, Lutsenko connected with a writer named John Solomon, who published several articles elevating later-retracted claims Lutsenko made about Biden and about then-Ambassador to Ukraine Marie Yovanovitch.

One of those articles, published on April 1, introduced the Biden-Shokin allegations to his audience. Two weeks later, talking to Sinclair Media Group’s Eric Bolling, Trump elevated the Biden accusations. The claims were “very big,” he said, adding that “Ukraine seems to be involved in a lot of things.”

“And you know with the people with respect to Manafort and all of them — nothing had to do with Russian collusion,” he said on April 17. “Nothing, not one.”

In an interview a week later with Fox News’s Sean Hannity, he suggested that Attorney General William P. Barr, then fairly new to the job, would be interested in investigating an allegation of Ukrainian interference promoted by Solomon.

On May 2, Barr announced an investigation into the origins of the Russian interference probe.

“I hope he looks at the U.K.,” Trump said at the time, “and I hope he looks at Australia, and I hope he looks at Ukraine. I hope he looks at everything, because there was a hoax that was perpetrated on our country.”

The next day, Trump spoke on the phone with Putin. It was the first time the two had spoken since late November, when, after Trump canceled a one-on-one meeting in response to tensions between Russia and Ukraine, he engaged Putin in an extended, unscheduled conversation. Six days later, Giuliani told the Times he was heading to Ukraine to do some investigating of his own.

By then, both the interference and Biden claims were fully incorporated into Trump’s theory of Ukraine. From April 17 to June 19, he mentioned the Biden theory five times to reporters or in interviews. He made reference to Ukraine and interference twice, including telling Hannity in mid-June that he should “take a look at Ukraine.”

“How come the FBI didn’t take the server?” he then said. “Podesta told him to get out. He said, ‘Get out.’ ”

None of this shows that the seeds of Trump’s focus on Ukraine came solely from Putin. It does, however, demonstrate the timeline during which Trump seized upon the theories that he presented to Zelensky in late July.

There have been more than two dozen times since Trump took office that he’s mentioned specifically having spoken with Putin about Ukraine. It seems unlikely that those conversations were focused solely on Trump’s theory of how to achieve peace between the two countries.

Last month, with the impeachment push in full force, Putin broached the subject of election interference.

“Thank God,” he said at an event in Moscow, “no one is accusing us of interfering in the U.S. elections anymore. Now they’re accusing Ukraine.”