During his recent “60 Minutes” appearance, Mr. Cernovich said that he never named the pizzeria at the center of the #Pizzagate conspiracy theory and called the shooting a “very unfortunate thing.” He also said his claims about Mrs. Clinton’s health were based on an anonymous tip sent to him by a doctor who had never examined Mrs. Clinton before and had no access to her medical records. Nevertheless, he stood behind his claims.

“They’re definitely not fake,” he said. “They are not lies at all. 100 percent true.”

Why is he in the news this week?

In a blog post published on Sunday, Mr. Cernovich wrote “the White House Counsel’s office identified” Susan E. Rice, President Barack Obama’s national security adviser, “as the person responsible for the unmasking” Trump associates who were caught up in the electronic surveillance of foreigners. Similar reports were published by other news organizations.

“Unmasking” is the process by which a high-ranking official, such as a national security adviser, requests the identity of a person whose name has been blacked out in an intelligence report. It does not mean leaking that information to a third party.

Donald Trump Jr. praised Mr. Cernovich’s post on Twitter and said he was the first person to publish this information. In an email on Tuesday, the president’s son declined to answer questions on the record about Mr. Cernovich or his blog post.