Here’s an interesting, prescient read from former Obama White House Counsel Bob Bauer, writing at justsecurity.org back in July. Note the reference to Wikileaks in light of the news this afternoon of a correspondence between Donald Trump, Jr. and Wikileaks.
Here’s the key passage …
A charge of illegal coordination is consistent with a conspiracy, aiding or abetting, or “substantial assistance” source of liability. It is the campaign finance law equivalent to what has been referred to in the public debate as “collusion.” In other words coordination is a legally prohibited form of collusion: spending by Russia, if coordinated with the campaign, is a contribution to the campaign. The contribution, of course, would be illegal. It is important to underscore here that this area of law applies to any and all coordinated spending beneficial to the campaign, not only to coordination with Russians, the Russian government, or other foreign nationals (think: Wikileaks).
These are more technical legal infractions that are distinct from the larger issues with conspiring with a foreign government. But the law seems pretty clear.