The point of the memo written by House Intelligence Committee Chairman Devin Nunes (R-Calif.) and released Friday afternoon was supposed to be to expose corruption at the highest levels of the FBI. But what the memo actually did — albeit surely not intentionally — was exactly the opposite. In a brief 3½ pages, Nunes managed to confirm that the investigation into the Trump campaign’s possible ties with Russia has a very solid basis and that special counsel Robert S. Mueller III must keep looking into the case.

As a former special agent for the FBI working on counterintelligence, I used to obtain Foreign Intelligence Surveillance Act warrants, so I’m familiar with the procedures Nunes implies the FBI abused in this case. To initiate surveillance on former Trump foreign policy adviser Carter Page in October 2016, the government would have had to demonstrate that Page was “knowingly engaging in clandestine intelligence gathering activities for or on behalf of” Russia. Importantly, the “knowingly” requirement applies only to “U.S. persons” such as Page, not to foreign nationals — which means the government had a slightly higher burden in his case. It takes months and even years to obtain enough relevant evidence for a FISA application, which can include details from physical surveillance, phone and financial records, items recovered from the target’s trash and intelligence obtained from other sources. So the FISA application would probably have outlined the bureau’s efforts going all the way back to 2013, when Page was approached by the FBI, which warned him, based on recordings of Russian intelligence officers, that he was being targeted for recruitment as a Russian spy. (That same year, Page also reportedly wrote in a letter to an academic publisher that he was an “informal advisor to the staff of the Kremlin.”) In counterintelligence investigations, this kind of interview would have been intended to “neutralize” the Russians: The idea is that anyone who was being unwittingly developed as a spy, as Page appeared to be, would be dismayed to realize what was happening and would immediately cease further contact with their intelligence contacts.

That means that three years before the FISA surveillance on him began, Page was on notice regarding exactly whom and what he was dealing with when it came to the Russians. For the FBI to get a warrant to listen to his communications later, the bureau would have had evidence that Page remained in contact with individuals he knew were affiliated with Russian intelligence. And the FBI would have had to demonstrate to the FISA court that Page was engaging in behavior that appeared to be facilitating Russia’s intelligence activities. (Those could include things such as frequent and potentially secret meetings with Russian intelligence officers; utilizing tradecraft like communicating in code; or accepting payments from known intelligence sources.) This time period, of course, covered his participation in the Trump campaign: Trump identified Page as an adviser in March 2016 in an interview with The Washington Post, although he had left the campaign in September 2016 following news reports of his connections in Russia. (This means the FBI did not intercept his communications until a month after he stopped working for Trump.) The three years after the bureau first warned Page would have been plenty of time for Russian intelligence to develop him as an intelligence asset and to capitalize on his assessed vulnerabilities, which included his desire to make money and move up professionally.

Nunes’s memo also discloses that the government obtained three renewals of the FISA warrant, which occurred every 90 days after the initial authorization. In order for a judge to allow the surveillance to continue, the government has to demonstrate that the intercepted communications are, in fact, providing foreign intelligence. In Page’s case, the order would have been initially authorized based on the premise that monitoring his communications was necessary to understand what, exactly, Russian intelligence was doing and how Page played a role in those activities. If, 90 days later, the government had not obtained any new information about Page’s contacts and activities and the surveillance had ceased, that would show that Page probably was not working as a spy and that the evidence that had seemed to point in that direction was wrong. Instead, the continued renewals underscore that the government was able to persuade the court that Page continued his contacts and activities.

If Nunes was trying to cast doubt on the basis and motives for the FBI’s interest in Page and in his campaign, he failed miserably. Far from demonstrating that the FBI was out to get Trump, the memo suggests that the Trump campaign could have had an active Russian spy working as a foreign policy adviser. Nunes suggests that the FISA applications were flawed because they included some information supplied by former British intelligence officer Christopher Steele, who was hired by an opposition-research firm funded by the Clinton campaign. But as a matter of law, that shouldn’t have made a difference to the court, especially if the affidavit had plenty of other supporting evidence of Page’s activities. Notably, the memo doesn’t even attempt to argue that Page did not, in fact, have ties to Russia.

Even worse for Nunes, he managed to showcase concrete proof that the FBI was looking into Trump’s Russian connections before they heard from Steele. The memo confirms that Australian intelligence was aware of possible ties between George Papadopoulos, another Trump campaign foreign policy adviser, and Russian intelligence, and that the Australians were alarmed enough to alert the FBI, which opened an investigation in July 2016.

Papadopoulos, of course, pleaded guilty in October to lying to the FBI about his contacts with Russia and has been cooperating with Mueller’s investigation. So has former national security adviser Michael Flynn. Trump’s former campaign manager, Paul Manafort, has been charged with failing to register as a foreign agent for Ukraine even though his firm was paid $17.1 million by a Ukrainian political party with ties to Russia. And then there are all the multiple approaches made by individuals connected to Russian intelligence to Donald Trump Jr., Jared Kushner and Jeff Sessions. Every one of them has lied when asked about their Russian contacts.

So what the memo reveals about Page is cause enough for concern. And in the context of everything else we know so far, it is downright alarming.

Whether there was ultimately any collusion between Russia and individual members of the Trump campaign, there can be no doubt after the memo that the government had good reason to investigate Russian attempts to place and recruit assets there. Any American who cares about protecting our elections and democratic processes from foreign interference should want no stone unturned in exposing how successful Russia was in its efforts. Nunes may have thought he was proving the FBI was out to get Trump. Instead, he proved the FBI was right to worry.

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