Public discussion of the FBI's ongoing investigation into Russian influence on the 2016 election is dominated by the question of collusion: Were senior members of the Trump campaign knowing collaborators in the Russian government's campaign to undermine Hillary Clinton's candidacy? My own view is that we're unlikely to get any truly conclusive evidence of this—but also that it's a mistake to treat it as the only important question for an investigation to answer.
There are two main reasons I doubt we're going to get any smoking gun proof of secret coordination between Russia and Trump's campaign. The first is simply that, even if it had happened, there's no reason to expect that unambiguous evidence of it would necessarily be available to the FBI. Collusion, after all, is ultimately a question of the conversations people had—and in this case you'd expect that at least on the Russian side there would be an acute understanding of the need to keep those conversations secret. If those conversations were conducted in person, there's no real way to retroactively prove what was said unless one of the participants confess. If they were telephone conversations, the same applies unless one of the parties happened to be under electronic surveillance at the time (and using an actively monitored communications facility). Absent that, you might be able to show a suspicious volume of contacts, but on the critical question of what was said, you'd be out of luck. Conspiracy is just inherently a hard thing to prove unless one of the conspirators flips or is dim enough to leave a paper trail.
That's actually secondary, however. The primary reason I doubt we're going to see that smoking gun is that it's hard to see why it would be in Russia's interest to loop the Trump campaign in on their interference campaign. The risks would be significant, and the benefits hard to discern. As Lawfare observed last month, there is ample evidence of collusion and coordination between the Trump campaign and Russia—it's just that all of it took place right out in the open. Russia's efforts on Trump's behalf were, for the most part, pretty open, even if Trump affected not to notice them. Trump's praise of Vladimir Putin—grounded in an affection that long predates his political career—was public, as was his gleeful exploitation of the fruits of hacks against his opponents and encouragement of more of the same, as was his attempt to exculpate Russia long after the intelligence community had reached consensus about their responsibility, as was his use on the campaign trail of stories pushed out by Russian state media. Trump could see they were helping him, they could see he appreciated it and was reciprocating. What, exactly, would have been the marginal benefit of some further secret communication making this happy symbiosis a matter of explicit agreement? Collusion would have been redundant.
One benefit might be apprising the Trump campaign about what to expect, or inquiring as to what forms of assistance would be most useful. But none of that requires the kind of explicit confirmation of a state-sponsored information operation that people have in mind when they talk about "knowing collusion." All of that could be accomplished via cutouts that preserve plausible deniability. So, for instance, Trump confidant Roger Stone appeared to have advance knowledge of forthcoming Wikileaks dumps of hacked Democratic e-mails, and acknowledged communications with both Julian Assange and the "Guccifer 2.0" hacker persona, now widely regarded as a front for Russian intelligence. If Russia wanted information from the campaign, or to privately convey information to the campaign, they clearly had a plethora of channels to do it without anyone concerned having to say out loud: "Vladimir Putin is trying to influence the presidential election, and here's how we can coordinate our efforts."
Now consider the liabilities. Such coordination would backfire disastrously if exposed. The Intelligence Community might detect it. The notoriously erratic Trump might tweet something indiscreet at 3 a.m. Someone on his staff might blow the whistle, whether prompted by a belated attack of patriotism or more self-serving motives. All of it would be an intolerable risk, for everyone involved. Intelligence generally operates on the principle of "need to know"—and nobody within the campaign needed to know.
The only real benefit on Russia's side to making the cooperation explicit would have been the ability to extract some sort of quid pro quo beyond what Trump was prepared to publicly commit to during the campaign, and the leverage the campaign's complicity would provide. But some of campaign staff, at least, would surely have realized as much themselves: The only real motive for making collusion explicit and covert rather than tacit but overt would be the added leverage it gave Russia over Trump. Realizing this would give them strong self-interested reasons to defensively expose such an overture, which in turn would increase the downsides for Russia in making them. I find it much more plausible that there was so much publicly observable implicit coordination precisely because direct, private coordination didn't make sense for either side.
Probably the best counterargument to this line of reasoning is that Trump continues to behave for all the world like a man desperate to hide something. But that could be any number of things other than direct and explicit conspiracy with self-identified Russian intelligence operatives. I won't indulge in lengthy speculation about the range of possibilities here, but if the FBI is spending months turning over rocks, scrutinizing the personal and financial ties between Trump or his associates and Russian officials or businesses, there's a pretty good chance of bumping into any adjacent unseemly or unlawful conduct in the process, even if they come up empty on a conspiracy to affect the outcome of the election. To the extent that anything along those lines is known to Russia, it's a potential source of leverage over anyone in the administration who'd be implicated by its disclosure.
Alternatively, Russian operatives may well have found ways to manipulate, extract information from, or gain influence over members of the Trump team who were unaware of it at the time. Critics of the administration seem to want the moral satisfaction of demonstrating that campaign officials were witting and culpable co-conspirators in Russian influence operations, rather than pawns or dupes. But the latter is as serious a scenario from a national security perspective, even if it makes a less tidy morality play.
It therefore seems like a grave error to talk as though the two possible outcomes are that the FBI's investigation—or that of a special counsel, if that's the direction this ends up going—either finds clear evidence of knowing collusion or turns up nothing much worth talking about. The more we focus obsessively on that first unlikely alternative, the easier it becomes to sweep any other significant findings under the rug once the investigation concludes, by limiting public disclosure of those findings to a terse answer to the binary question of collusion. Probably James Comey would have been difficult to bully into complicity in such a whitewash, but he's gone now, and the more the public is convinced that's the only question worth answering, the easier his successor will find it to play ball.