As part of the larger "Crossfire Hurricane" investigation into Russia's efforts to interfere in the 2016 presidential campaign and possible involvement by persons in the Trump campaign (see pages 50-59 of Inspector General Horowitz's Report for a detailed account of the basis for "Crossfire Hurricane"), the FBI opened a specific counterintelligence investigation concerning Flynn ("Crossfire Razor") on August 16, 2016.  The Flynn investigation was based upon "an articulable factual basis that [he] may wittingly or unwittingly be involved in activity on behalf of the Russian Federation which may constitute a federal crime or threat to the national security."  That, in turn, was predicated upon an assessment of "reliable" lead information, including that Flynn had been a foreign policy adviser to Trump since February 2016; that he "had ties to various state-affiliated entities of the Russian Federation"; that he traveled to Russia in December 2015; and that he had an active TS/SCI security clearance.

There was nothing suspect or unreasonable about opening this counterintelligence investigation of Flynn.  And as the DOJ Inspector General later concluded, the FBI's "predication" to open that investigation was more than sufficient to satisfy the modest threshold prescribed by DOJ and FBI policies. [...]

The second series of calls between Flynn and Kislyak commenced less than one week later, on December 29, just hours after the United States had imposed sanctions on nine Russian individuals and entities, expelled 35 Russian government officials, and closed two Russian government-owned compounds in the United States, all in response to Russia's interference in the 2016 presidential election.  President-Elect Trump expressed a lack of concern about Russia's election interference.  When asked about the sanctions, he responded:  "I think we ought to get on with our lives."

After discussing the matter with members of the transition team, including Michael Ledeen and K.T. McFarland, Flynn called Kislyak to urge Russia not to escalate the situation in the manner the U.S. expected it to do.  Flynn at the very least implied to Kislyak that the Trump Administration would be more conciliatory to Russia, notwithstanding its election interference, and he may even have suggested that Trump might alleviate the sanctions Obama had imposed that very morning.  [UPDATE:  Flynn implored Kislyak to convey to Moscow that it should "not allow this [Obama] administration to box us in right now."  Flynn also said to Kislyak, "Let's keep this at a level that uh is, is even-keeled, okay? ls even-keeled. And then what we can do is, when we come in, we can then have a better conversation about where ... we're gonna go ... regarding our relationship."  He also criticized the Obama administration's "position on the Middle East," saying that it "doesn't do anybody any good."] Unlike with respect to the first call (about the UNSC resolution), in this case Russia did as Flynn asked:  Vladimir Putin decided not to escalate the conflict, presumably assured that Trump would ease up on the U.S.'s objections to Russia's election interference.  [On December 31, Kislyak conveyed the news to Flynn, adding that "We are hoping within two weeks we will be able to start working in [a] more constructive way."]

To hear DOJ now tell it, those late-December calls were of no moment, and shouldn't have affected the FBI's decision to close the Flynn investigation.  The most alarming and revealing passage in the DOJ motion to dismiss the charge against Flynn is this one--in particular the bolded sentence:

With its counterintelligence investigation no longer justifiably predicated, the  communications between Mr. Flynn and Mr. Kislyak--the FBI's sole basis for resurrecting the investigation on January 4, 2017--did not warrant either continuing that existing investigation or opening a new criminal investigation.  The calls were entirely appropriate on their face. . . .  Mr. Flynn, as the incumbent [sic] National Security Advisor and senior member of the transition team, was reaching out to the Russian ambassador in that capacity.  In the words of one senior DOJ official [Mary McCord]:  "It seemed logical . . . that there may be some communications between an incoming administration and their foreign partners."   Such calls are not uncommon when incumbent [sic] public officials preparing for their oncoming duties seek to begin and build relationships with soon-to-be counterparts.

This is absurd--akin to Trump's assertions in 2019 that his communications with the Ukraine, urging officials of that nation to announce an investigation of Hunter and Joe Biden, were "pitch perfect."  It's shocking the Executive branch would write such a thing in a brief to a court.  The Flynn/Kislyak calls were the furthest thing from "appropriate."

For one thing, the apparent substance of the call on December 29 was, at a minimum, deeply disturbing.  Flynn apparently was signaling to Kislyak that the Trump Administration would be more conciliatory to Russia, notwithstanding its election interference, than the Obama Administration had been--up to and including an implication that Trump might well alleviate the sanctions Obama had imposed that very morning.  (Putin presumably wouldn't have done if he didn't have reason to believe the Trump Administration would be more conciliatory with respect to the election interference matter.)

The question of why Trump, Flynn, et al., were--and continue to be--so in thrall to Vladimir Putin, or at the very least indifferent to Russia's threat to our electoral system, continues to be perhaps the most consequential question of the Trump Presidency.

Even apart from the merits of what Flynn said, however--that is to say, even if you happen to agree with Trump's views on Russian sanctions and/or on the U.N. vote regarding Israeli settlements--it's inappropriate for a member of a presidential transition team to communicate with foreign officials secretly about current U.S. national security or foreign policy matters (i.e., without the knowledge of the State Department or some other process for informing the current Administration), and far worse still to do so in an effort to undermine the national security or foreign policy objectives of the United States as determined by the President then in office.

According to the New York Times, the Obama Administration had made a "pointed request" to the Trump transition team to avoid sending conflicting signals to foreign officials before the inauguration and to include State Department personnel when contacting such officials.  That's fairly standard-issue stuff, as reflected in the Partnership for Public Service's widely consulted Presidential Transition Guide.  It was wrong for Flynn to disregard the administration's request and the longstanding norm--and particularly to do so in the way he did here.  Contrary to the two Freudian slips in the DOJ brief, Flynn was not the "incumbent National Security Advisor" at the time--Susan Rice was.  DOJ is right that incoming officers commonly communicate during the presidential transition with their future foreign partners so that they can "begin and build relationships with soon-to-be counterparts."  Friendly congratulatory calls and innocuous, generic "I look forward to working together" communications are commonplace.  It's another thing entirely, however, to signal a subversion of the sitting President's foreign policy objectives--let alone to do so secretly, so that the U.S. government is unaware of what's being said and done.  (To be sure, the government in this case eventually discovered what Flynn and Kislyak discussed, but not for several days, during which time the State Department and other agencies were in the dark about what Putin was up to and why.)

Moreover, this wasn't just any foreign counterpart or an ordinary transition context--Flynn was speaking to a representative of the nation that had just hacked the American election campaign in an effort to have Trump elected, and doing so mere hours after the President of the United States had responded decisively.  As Director of National Intelligence James Clapper saw it, Flynn had "essentially neuter[ed]" the just-imposed sanctions.*

Indeed, the wrongfulness of Flynn's actions was so manifest that when word of the conversation with Kislyak became public (see Point 8, below), it infuriated President-Elect Trump, who instructed Reince Priebus to direct Flynn that he had to "kill the story."  Flynn then told K.T. McFarland that "I want to kill the story," and asked her to call the Washington Post and deny that Flynn had discussed sanctions with Kislyak.  As the Mueller Report recounts, "McFarland made the call as Flynn had requested although she knew she was providing false information, and the Washington Post updated the column to reflect that a 'Trump official' had denied that Flynn and Kislyak discussed sanctions."  As noted in Point 7, below, Flynn himself made the same denials to Priebus, Vice President-Elect Mike Pence, and incoming press secretary Sean Spicer.  (Flynn also omitted the discussion of sanctions from his written documentation of the December 29 Kislyak call, later acknowledging to Robert Mueller's Office that he did so "because it could be perceived as getting in the way of the Obama Administration's foreign policy."  (The quotation is the Mueller Report's characterization of what Flynn told the Mueller investigators.))  [...]

[UPDATE:  The reactions of many Trump/Barr/Flynn defenders to the transcripts of the December 29 call-in effect, that Barr's right that it's a big nothingburger at worst, if not "laudable" (see below)-prompts me to add the following about the heart of the huge disconnect respecting the Flyyn/Kislyak call:

We know now that Trump (at best) didn't care about Russia's election interference-he's said so daily for three-plus years.  And if that's your baseline understanding-that of course Trump wasn't troubled by the cyber-operations and therefore would naturally have been trying to stymie the effects of Obama's sanctions-then the reaction to the Kislyak call is:  "Duh!"

But on December 29 2016, the idea that the incoming President of the United States and/or his National Security Advisor would be so nonchalant about Russia's interference-in secret, with the Russian Ambassador!-was virtually unthinkable, shocking, and alarming, easily justifying DOJ's and the FBI's concerns.  And then things only got more troubling when the Vice-President-Elect offered a false public account.

Or, as David Corn writes, think about when this call was occurring and what the incoming National Security Advisor failed to say to the Russian Ambassador:

At no point does Flynn castigate Kislyak for Russia's intervention in the 2016 election.  He does not confront the Russian ambassador for Putin's covert operation to subvert American democracy.  He does not tell Kislyak that Moscow will have to pay a price for hacking the Democrats and using the stolen information to influence the election for Trump's benefit.  Flynn, a former head of the Defense Intelligence Agency, does not warn Kislyak against any further Russian information warfare targeting the United States.  As the Obama administration was trying to impose a punishment on Putin for that attack, Flynn, on behalf of the Trump gang, was sending an utterly different message:  We don't care about that.

Think about this perverse set of interactions: the incoming national security adviser was essentially telling a foreign adversary that the new president wasn't concerned about an attack on the United States and, moreover, indicating that Trump didn't intend to do anything about it.  In fact, Flynn was signaling to Putin that once Trump took office, Trump wouldn't be pursuing the matter and, instead, would be reaching out to Russia as a partner.  (A few months later, Trump, in the Oval Office, would tell Kislyak that directly.) . . .

He was dealing with the Russians as if there had been no attack.]