Former Trump campaign chairman Paul Manafort leaves U.S. District Court in Washington on Nov. 2. (Bill O'Leary/The Washington Post)

Investigators led by special counsel Robert S. Mueller III say former Trump campaign chairman Paul Manafort schemed with a person tied to Russian intelligence to sway public opinion in the United States.

One key point that is important to make clear: Prosecutors say Manafort did this after the election — last week, actually — meaning the allegation does not point directly to collusion between Donald Trump's camp and Russia during the presidential race.

In a motion filed Monday in federal court in Washington, investigators accused Manafort, who was indicted on multiple charges in October and is on house arrest, of collaborating with someone “currently based in Russia and assessed to have ties to a Russian intelligence service” on an op-ed on Manafort's political work for Ukraine that “clearly was undertaken to influence the public's opinion of defendant Manafort.”

Investigators said they discovered the op-ed before it was published. They did not name Manafort's writing partner or say where he hoped to publish the article but did say Manafort and his partner planned “to ghostwrite it in another's name” and “the proposed piece is not a dispassionate recitation of the facts.”

What we're talking about here is a joint effort by Trump's former campaign chief and a person connected to Russian intelligence to inject a slanted argument into the press while concealing the true source. This isn't the kind of collusion Mueller's team is looking for, but this is what that kind of collusion would look like.

It would look like a joint effort by the campaign and Russia to plant messages in American political discourse without leaving fingerprints. The only difference between the alleged collusion by Manafort and his co-author, and the possible collusion being probed by Mueller, is timing — before or after Election Day.

The difference is a big one, of course, but the natural question is whether Manafort pulled the alleged op-ed idea out of an old bag of tricks. Did Manafort think he could improve his public image by ghostwriting an article with a person linked to Russian intelligence because he had done something similar before or was this a new idea?

Another former top adviser to Trump, Michael Flynn, wrote an op-ed in the Hill on Election Day that hailed Turkey as “our strongest ally against the Islamic State in Iraq and Syria” and sharply criticized Fethullah Gulen, the Muslim cleric who Turkish President Recep Tayyip Erdogan says was behind a coup attempt last year. Flynn put his name on the piece, but what he presented as objective analysis was actually paid work on behalf of Turkish businessman Ekim Alptekin, owner of a Dutch firm named Inovo BV. Part of Flynn's mission was to pressure U.S. officials to act against Gulen.

Flynn is now cooperating in Mueller's investigation. Perhaps he can say whether members of the Trump campaign succeeded in publishing any other articles under false pretenses.