Incoming national security adviser retired Lt. Gen. Michael T. Flynn will meet with national security adviser Susan E. Rice for the first time Wednesday at the White House, as congressional criticism of Flynn increases regarding his penchant for spreading conspiracy theories and his comments on Islam.

Although Trump transition team members have been working inside the White House for weeks, Flynn has had only sporadic contact with Rice since the election, two sources close to the transition confirmed. Meanwhile, Flynn has kept up a steady schedule of meetings with foreign officials as he prepares to be the president’s top national security aide. The Flynn-Rice meeting could be an awkward one, considering that Flynn has repeatedly trashed President Obama’s foreign policy — as implemented by officials including Rice.

Moreover, although Flynn has a security clearance and participates in the presidential daily briefings, he has not signed the necessary paperwork for receiving detailed transition briefings that contain secret information. His Wednesday visit to the White House could be an opportunity to do so.

Meanwhile, Democrats in Congress are ramping up their criticism of Flynn and his recent behavior, especially his use of social media. Sen. Tim Kaine (D-Va.) told me the most troubling part of Flynn’s behavior is his long record of trafficking in conspiracy theories and other news items that later turn about to be fake, sometimes on issues that relate to national security.

“I have grave concerns about Flynn for a whole variety of reasons,” said Kaine, a member of the Senate Armed Services Committee and the former Democratic vice-presidential nominee. “He’s either so gullible to accept things that even a fourth-grader wouldn’t accept or he’s so consumed with malice that that overrides what should be a natural incredulity.”

Kaine suggested Congress might investigate Flynn’s behavior, even though the national security adviser does not need Senate confirmation: “I wish this were a Senate-confirmable position because we want to explore this further. We may have an opportunity on that, by the way.”

Kaine did not elaborate on how the Senate might explore Flynn’s behavior or suitability for the job of national security adviser. Senate Armed Services Committee Chairman John McCain (R-Ariz.), asked Tuesday if he had any concerns about Flynn, said, “None at all.”

Flynn has pushed fabricated or dubious stories on Twitter at least 16 times since August, according to a tally by Politico. Stories that have appeared on Flynn’s Twitter feed have included accusations that Hillary Clinton is involved in a child sex-trafficking ring, that she has waged a secret war on the Catholic Church, that Obama is a jihadi and that is a secret United Nations plot to take over the world called “Agenda 21.”

While he was director of the Defense Intelligence Agency, Flynn pushed his analysts to find evidence that Iran was linked to the Sunni jihadist attack on the U.S. mission in Benghazi, Libya, on Sept. 11, 2012, according to the New York Times. More recently, Flynn has embraced the Turkish government’s mantra that Fethullah Gulen is the head of “a dangerous sleeper terror network,” as he wrote in The Hill on Election Day. Flynn called for Gulen’s extradition to Turkey, getting ahead of an ongoing Justice Department review of the issue.

Flynn’s penchant for spreading false or misleading information came under closer scrutiny this week when his son, Michael G. Flynn, continued to propagate the false story that a D.C. pizza restaurant was the center of a Clinton-linked child sex-trafficking ring, even after a gunman opened fire in the restaurant in an attempt to investigate the false story.

After Vice President-elect Mike Pence said that Flynn’s son wasn’t involved in the transition effort, transition spokesman Jason Miller told reporters Tuesday that the younger Flynn had been assisting his father but would no longer do so.

But a source familiar with the transition said the Trump transition team had requested a security clearance for Flynn’s son before the latest controversy.

Also on Tuesday, 53 mostly left-leaning nonprofit organizations penned an open letter to Trump asking him to dump Flynn for a range of comments he has made about Islam, including tweeting that “fear of Muslims is rational” and that “Islam is a political ideology” that “hides behind being a religion.”

Several transition sources said Flynn is heavily involved in selecting a range of potential national security officials for Trump’s incoming administration. The Trump team is also thinking about drastically reducing the size of the National Security Council staff, from about 400 where it stands now to as few as 100 staffers.

Congress set a ceiling of 200 staffers for the National Security Council in next year’s defense authorization bill as an attempt to rein in the size of what was then expected to be Hillary Clinton’s NSC staff.

Flynn’s engagement with Rice is a positive, if belated, step toward his transformation from a decorated intelligence officer to a conspiracy theorist to being the official in charge of coordinating the entire national security bureaucracy and implementing U.S. foreign policy. The more real facts she can give him, the better.