Sergey Kislyak reported to his superiors in December that Jared Kushner, President Trump's son-in-law and adviser, asked him about setting up a communications channel between the transition team and the Kremlin using Russian facilities in the United States. (Alice Li,McKenna Ewen/The Washington Post)

The Washington Post's national security team just reported that during the transition, Jared Kushner proposed to the Russians that they set up a secret channel of communication using secure Russian facilities. That's what the Russian ambassador to the United States told Moscow about a December conversation he had with Trump's son-in-law and top adviser.

This is a damning piece of news for the White House caught under an avalanche of revelations about its dealings with Russia.

If it's true, it's the most difficult for them to explain in the context of an FBI investigation into Russia meddling in the U.S. election and whether Trump's campaign helped. Why would Trump's transition team need to secretly talk to the Russians, using their Russian channels?

The White House declined to comment.

Everything we've learned these past few weeks as it relates to the FBI's investigation into Russia is noteworthy, but it can be caveated with a reasonable explanation from the Trump White House. This news is much more difficult to caveat.

To wit:

1) Kushner is now a focus of the FBI's investigation into Russia meddling. Of interest to FBI investigators is likely Kushner's several meetings with the Russian ambassador.

Caveat: The FBI has accused Kushner of no wrongdoing, and he's not their main focus.

2) Kushner didn't share those meetings with the Russians on his security clearance form. A security clearance is required for anyone who is privy to the nation's deepest secrets.

Caveat: His lawyer said it was a mistake, and Kushner corrected it after the New York Times reported it.

3) CNN reported Friday that FBI investigators are also interested in how Russia helped use computer bots to target and push negative information on Hillary Clinton (and positive information about Trump) on Facebook. Trump campaign's data analytics operation was supervised by Kushner.

Caveat: Kushner ran a media company, so it conceivably makes sense he'd take over social media for the campaign.

4) Now we learn that Kushner proposed setting up a secret communications channel between Trump's transition team and Russia using Russian facilities, according to Russia ambassador's report home. U.S. officials told The Post this was an apparent move by Kushner to block any monitoring of Trump's activities ahead of the inauguration from the United States.

Here, we have a caveat: Russians at times feed false information into communication streams that they think the United States is watching.

But we have a caveat to that caveat: It's unclear why the Russian ambassador, Sergey Kislyak, would misreport his conversations to his own people. (Although it's conceivable Kislyak was exaggerating or misunderstood what was said.)

What you need to know about Jared Kushner's ties to Russia. (Thomas Johnson/The Washington Post)

This news also feeds directly into what the FBI, a special counsel and multiple committees in Congress are investigating: Did Trump's campaign work with Russia to influence the election?

Secret back channels. Meeting with the Russians. Forgetting to disclose your meetings with the Russians. (Kushner is just one of several current and former Trump campaign officials who held meetings with the Russians, then forgot to share those meetings.)

If the Trump campaign did not work with Russia to try to influence the election, they certainly had a lot of interactions with the Russians that they didn't want the U.S. government and/or the public to know about.

Which raises the question: What reason would Kushner have to keep talks secret from the U.S. government, when his father-in-law was a month away from being the head of the U.S. government?

Obama officials told Washington Post reporters that the best they can surmise is perhaps Trump's campaign was afraid it'd get out to the media that they were trying to talk to the Russians. News was breaking that U.S. officials thought Russia meddled in the election, and Kushner may have recognized how politically sensitive it would be to meet with the Russians.

It's not unusual for campaigns and transitions to have conversations with foreign leaders, but in this context, it is weird for U.S. campaigns to meet with Russians. It's also unusual for transition teams to request sensitive ways to communicate with foreign governments. And it's really unusual to request a foreign government's help communicating secretly, which is what the Russian ambassador told Russian officials Kushner asked for.

Well before any of this was public, Team Trump's meetings with Russians raised eyebrows for former CIA director John Brennan, who told Congress recently:

"[B] the time I left office on January 20, I had unresolved questions in my mind as to whether or not the Russians had been successful in getting U.S. persons involved in the campaign or not to work on their behalf, again, either in a witting or unwitting fashion. And so, therefore, I felt as though the FBI investigation was certainly well-founded and needed to look into those issues."

Since then, revelations about the Trump campaign's relationship with Russia have made their interactions look more — not less — suspicious. That Kushner may have tried to establish secret communications with the Russians tops that list.