House investigators have scheduled an interview with the Trump campaign digital director to question him about any campaign coordination with Russian-financed Internet advertising. Amid all the intense attention to obstruction of justice issues, this is a timely reminder of the central question of Trump campaign collusion with Russian interference in the election.

As argued here and here, Trump campaign liability would be grounded in a provision of the campaign finance laws prohibiting “substantial assistance” to a foreign national in an electoral intervention. It is new territory for a prosecution under this law: the government has not applied the regulation in circumstances like these.  The question has not come up, as it could not have: there have been no comparable circumstances.  Also, on the facts known so far, the Trump campaign’s actions in support of the Russian program have been “in plain sight”—carried out openly and notoriously.  So it may seem to some observers that, even if not requiring any stretch of the plain language of the rule, the substantial assistance theory is novel. They may hesitate to see it deployed in a case involving, at least in part, political campaign speech, namely, what the Trump campaign would prefer to characterize as routine commentary on the Wikileaks disclosures.

It may be easier to appreciate the case to the contrary–that liability with the requisite intent could be imposed for these actions–by considering how the case could also be brought under ordinary “aiding and abetting” principles of the criminal law.

It is well understood that established “aiding and abetting” principles have wide, elastic application. The abettor is not required, of course, to have been “in on it” from the beginning. In Learned Hand’s classic formulation in United States v. Peoni, the law requires only “that he in some sort associate himself with the venture, that he participate in it as in something that he wishes to bring about, that he seek by his action to make it succeed.”  The courts have defined in various terms this association, but what is required is “some affirmative conduct designed to aid in the success of a venture with knowledge that [the]actions would assist the perpetrator, the principal of the crime.” United States v. Cowart, 595 F.2d 1023, 1031(1979).

Note that the assistance constituting aiding and abetting does not have to be substantial. The accomplice liability provision of the federal campaign finance law, focused on “substantial assistance,” is, in that sense, stricter. So federal prosecutors proceeding on an “aiding and abetting” theory may have the latitude to reach a broader range of Trump campaign conduct in support  of the Russian program.

It would not be the first time that Prosecutors would have enforced campaign finance law with an “aiding and abetting” charge.  And they have evidence in the Trump/Russia case with which to work.

The campaign was fully aware of the Russian source of the stolen material and of the Putin regime purpose to intervene in an election.  The hackers did not steal into the Podesta account for their private consumption and edification; they put the stuff out with fanfare, with the intention of generating sensational disclosures that would have the most impact possible on the presidential campaign.  Understanding the foreign national aim, the campaign welcomed the intrusion and did what it could to advance its objectives. The national party over the course of the month of October issued multiple releases highlighting whatever it judged politically useful in the content of the Wikileaks disclosures. The President himself, who had openly invited the Russian hacking and declared that he “loved “ Wikileaks, cited this material in the closing weeks.   His confidante Roger Stone has made various and inconsistent statements about whether he had advance knowledge of the Wikileaks document releases, and there remains an open question of what he knew and how he came to know it; but he certainly amplified the disclosures by promoting them in advance and afterwards.

Even after the intelligence community finding, Mr. Trump participated in a presidential debate in which he would not denounce the Russian involvement, or even squarely acknowledge that there was no question that Russia was behind the hacking. Was this part of a strategy to send the needed message to his Russian political allies–a wink and nod?  If so, the Trump campaign did not stop at signaling its approval of the Russian theft. It then made active and systematic use of it.

One reason for the uncertainty about whether the Trump campaign may have accomplice liability is the focus on the hacking, the preliminary illegal act by which the Russians acquired the emails.  It showed up, remarkably in Attorney Sessions’ recent testimony to the Senate Intelligence Committee.  He defined the Russian activity as a “serious matter,” because it involved “hacking into a private person or DNC computer and obtaining information and spreading that out.”  “It’s an improper thing,” he told the Committee.

So Mr. Sessions suggested in this way that the illegality consisted narrowly of the hacking and the transmission via Wikileaks of the purloined emails. If the Trump campaign had no direct hand in that “serious matter,” then it could have done nothing improper. Indeed, there is no evidence, and little likelihood, that the Trump campaign helped the Russians infiltrate the DNC computer system or helped arrange for Wikileaks publication.  It could not have aided and abetted that particular illegal act. The confused talk about “collusion” suggests that those who deny it  should be asked which collusion–and what kind–they are disputing.

What is too often lost in the crossfire of charges and denials is that the Russians hacked the emails as a means to an end–the distribution of the emails and influence through these acts in the presidential election.  The Trump campaign unquestionably associated itself with this venture and wished for it to succeed.  The Republican nominee said so.  His actions and those of his campaign represented an  “affirmative conduct designed to aid in the success of a venture with knowledge that [the]actions would assist the perpetrator, the principle of the crime.”  The crime was foreign spending–providing any “thing of value”–in a U.S. election. It is not taking an expansive or tenuous reading of the law to see that the Trump campaign was engaged in “aiding and abetting” that.

This is the other notable aspect of the strange testimony from the Attorney General on this issue. He seemed to believe that the issue warranting investigative attention was electoral “impact” of the illegal Russian activity.  From Mr. Sessions’ perspective, any “impact” in the election could be traced directly from the illegal hack through the Wikileaks publication to the American electorate, and the Trump campaign was just one hapless member of the audience.

The Attorney General is badly mistaken in his understanding of the legal significance of what transpired in 2016 when the Russians committed cyber-crimes to affect the US election.  Whatever the actual “impact” of the Wikileaks disclosure, the intervention was illegal.  The Trump campaign’s encouragement and exploitation of this violation of law exposes it to accomplice liability.  This liability could be based on the prohibition on supplying “substantial assistance” to the Russian scheme, or on the application of “aiding and abetting” doctrine as it has been brought to bear in other campaign finance law prosecutions.

The thrust of the prosecution is the same in both cases, though arguably the evidentiary threshold is higher, at least less certain, for “substantial assistance.”  The evidence as it is further developed will determine which theory, if not both, is ever put to the test.

[For more analysis by Bob Bauer of developments in the case of the Trump campaign and Russian involvement in the 2016 presidential election, read Part I and Part II of this series. You may also be interested in Bauer’s “Open Door to Moscow? New Facts in the Potential Criminal Case of Trump Campaign Coordination with Russia” and “Considering the Legal Defenses of the Trump Jr. Meeting”]

Image: Brad Parscale, Donald Trump’s campaign digital director, arrives at Trump Tower, December 6, 2016. Pascale is reportedly scheduled to interview as a witness in the House Russia investigation – Drew Angerer/Getty Images