National correspondent

To hear President Trump tell it, FBI agent Peter Strzok was hopelessly biased against him and his candidacy. Trump has tweeted criticisms of Strzok repeatedly, often in personally disparaging terms, and on at least two occasions has suggested that Strzok’s involvement in the investigation into Russian interference in the 2016 election had a specific goal: preventing him from becoming president.

Strzok was a central player in the dueling investigations during the 2016 campaign. He was involved in the initial investigation into former secretary of state Hillary Clinton’s use of a private email server and opened the investigation into possible connections between Trump’s campaign and the Russian effort to influence the election’s outcome. He was subsequently involved in special counsel Robert S. Mueller III’s continuation of that investigation until Mueller learned of texts Strzok sent to Lisa Page, another FBI employee with whom the agent was engaged in an extramarital relationship. Those texts included some disparaging Trump in stark terms, prompting Mueller to remove him from the effort last July.

Trump has highlighted those texts as evidence that the investigation into him is biased for months. The president retweeted a particularly significant one last month.

Two weeks later, in another tweet, Trump quoted Fox News’s Andrew Napolitano, asking if there was “a conspiracy in the Obama Department of Justice and the FBI to prevent Donald Trump from becoming President of the U.S.” — a conspiracy with Strzok at its center.

If there was such a conspiracy, of course, it didn’t work. Trump is president and, before the election, there was barely a public whiff that any investigation even existed. If Strzok’s idea was to “stop” Trump from becoming president, it was a spectacular failure.

In a written statement offered before he testified before the House Oversight Committee on Thursday, Strzok pointedly noted that there was no effort on his part to keep Trump from winning the White House — and, further, that he was one of only a few people who could have potentially leaked details from the investigation in an effort to block Trump’s victory.

“In the summer of 2016,” Strzok wrote, “I was one of a handful of people who knew the details of Russian election interference and its possible connections with members of the Trump campaign. This information had the potential to derail, and quite possibly, defeat Mr. Trump. But the thought of exposing that information never crossed my mind.”

This is a nearly impossible point to rebut.

Before Election Day, there were rumblings that Russia was engaged in the campaign in nefarious ways and that Russian President Vladimir Putin sought to see Trump win. There were rumors — theories, really — that Trump was more than happy to have Russia’s help or even might be aiding that effort. In the closing days of the campaign though, the two most important stories about the Clinton and Trump investigations were ones that solely worked to the eventual winner’s advantage.

On Halloween 2016, the New York Times detailed what was known about the investigation into Russian interference (an effort addressed earlier that month in an unusual public statement from the government). The headline, though, summarized the good news for Trump’s effort: “Investigating Donald Trump, F.B.I. Sees No Clear Link to Russia.”

“None of the investigations so far have found any conclusive or direct link between Mr. Trump and the Russian government,” the article read. Since Trump was inaugurated, of course, we’ve learned much more about links between the campaign and Russia — involving even members of Trump’s family. The effect of the story, though, was to quash those rumors about Trump’s motivations.

The other important story seemed, at the time, much bigger. A few days before the article above, former FBI director James B. Comey revealed that the FBI was looking at emails involving Clinton found on former New York representative Anthony Weiner’s laptop. A few days later, Comey announced that his initial evaluation of Clinton’s behavior remained unchanged even with the new evidence — but the damage was done. The announcement is often cited as the difference-maker in the close election results.

An important detail: The initial draft of the letter Comey sent to Congress to inform them of the new emails was reportedly written by Strzok.

Since Americans only learned about the scale of the investigation into the Trump campaign after the campaign was over, it’s been common to look at Strzok’s obviously anti-Trump texts in the context of what we know now. Put another way, there’s been a concerted effort to explain away precisely the contradiction that Strzok notes: If he didn’t want Trump to win, why didn’t he do something to keep Trump from winning? (And by extension, why do something that seemed very likely to hurt Clinton’s chances?)

We looked at this last month, exploring the various theories that have been offered to explain this away. The most common explanation is that Strzok didn’t think Clinton would lose, just as Comey indicated that part of the rationale for his revelation about the Weiner laptop was the expectation that Clinton would be the president-elect.

But that’s looking at the race from the context of Oct. 28, not, say, Nov. 4.

The Comey announcement came as Clinton held a small lead in the national polls. State polls suggested that she was likely to win, but by Nov. 4 FiveThirtyEight pointed out that a Trump victory was well within the realm of possibility even in those state surveys. Even on Oct. 28, FiveThirtyEight had a 1-in-5 chance of a Trump win; by Nov. 4, Trump’s odds were at 1-in-3.

If you were an FBI agent in possession of information about how an adviser to Trump’s campaign knew about the existence of emails stolen by the Russians that disparaged Clinton, or who knew about the extent of the relationship between Trump’s former campaign chairman and Russian interests, or who knew that there was an active surveillance operation underway targeting another former adviser to the campaign, or who knew God-knows-what-else the FBI knows that hasn’t been made public — why would you not interject that information in the few days before the election as the results were obviously tightening? That Clinton’s odds were not north of 90 percent (as has often been claimed since) was common knowledge, and if you were both ferociously committed to stopping Trump and had information that you believed might actually achieve that goal, why not actually release it?

But no evidence has emerged to suggest that Strzok leaked anything about what he knew. Even if Strzok and Comey released the information about Weiner’s laptop believing that Clinton was going to win, within a week of that announcement the trend looked far different. Nonetheless, Strzok appears to have done nothing to reveal what he knew.

Much of Trump’s dismissal of the Russia investigation hinges on this idea that Strzok was biased against him, tainting the entire probe through to Mueller’s efforts. As new Post-Schar School polling makes clear, this line of argument has helped shift perceptions of the investigation, with about half the country seeing the probe as more of a distraction than as something serious.

Believing the investigation is biased against Trump because of Strzok’s involvement, though, means believing that Strzok saw the investigation as a way to stymie Trump and, more importantly, that Strzok was willing to use the investigation to do so. As he himself notes, at the moment when he could have most directly interfered with Trump’s political ambitions, he didn’t.

The fairest assumption, then, is that the probe’s origins were precisely what Strzok (and others) have suggested: An effort to determine whether Trump’s campaign intentionally aided the Russian effort at interference.