Hillary Clinton hands a microphone to her husband, Bill Clinton, during a debate watch party at Craig Ranch Regional Amphitheater in North Las Vegas on Oct. 19. (Andrew Harnik/Associated Press)

First we learned that the FBI's decision to resume probing the contents of Hillary Clinton's private email server was prompted by a story in a British tabloid. Now the New York Times is reporting that a separate investigation of the Clinton Foundation has unlikely source material of its own: a book called “Clinton Cash,” written by Breitbart News senior editor at large Peter Schweizer, which Breitbart chairman and Donald Trump campaign chief executive Steve Bannon turned into a documentary-style film.

If you are a Clinton supporter or, for that matter, anyone who is disinclined to trust information from Breitbart — a nationalist news site that puts Trump ahead of truth — your reaction might resemble that of Salon contributing writer Heather Digby Parton.

Indeed, the idea that the FBI would deem Breitbart hysteria worthy of investigation seems absurd on its face. But let's revisit the Times' book review of “Clinton Cash” from April 2015:

In the long lead up to Mrs. Clinton’s campaign announcement, aides proved adept in swatting down critical books as conservative propaganda, including Edward Klein’s “Blood Feud,” about tensions between the Clintons and the Obamas, and Daniel Halper’s “Clinton Inc.: The Audacious Rebuilding of a Political Machine.”

But “Clinton Cash” is potentially more unsettling, both because of its focused reporting and because major news organizations including the Times, The Washington Post and Fox News have exclusive agreements with the author to pursue the story lines found in the book.

That's right. At least some of Schweizer's reporting checked out and informed mainstream news reports. The Washington Post reported last April that “Bill Clinton was paid at least $26 million in speaking fees by companies and organizations that are also major donors to the foundation he created after leaving the White House.” The Post reported that story independently but pursued it after receiving an advance copy of “Clinton Cash” and signing a nondisclosure agreement with publisher HarperCollins.

The New York Times used a lead in “Clinton Cash” to report last April that firms that stood to profit from a deal for Russia to take over some U.S. uranium deposits donated millions to the Clinton Foundation. Hillary Clinton was secretary of state at the time, and the State Department was one of several agencies that had to approve the agreement.

As The Post and the Times drew from “Clinton Cash,” longtime political reporter Susan Milligan wrote in U.S. News & World Report that it would be unfair to dismiss Schweizer's book out of hand.

“Consider the source” is a basic tenet of good reporting. When someone tells you something, some of the internal questions a reporter must ask are: What is this person’s agenda? Does he or she have an axe to grind, or a financial or political stake in getting this information out? Does that person’s vested interest affect the legitimacy or credibility of the story?

But when a source, no matter how agenda-driven, offers up actual, hard information, based on public records, the motivation becomes meaningless. And this is why Hillary Clinton and Bill Clinton (along with their loyal team of defenders) must expect news outlets to scour and report out every accusation made in a new book by Peter Schweizer, author of “Clinton Cash: The Untold Story of How and Why Foreign Governments and Businesses Helped Make Bill and Hillary Rich.”

Milligan probably did not imagine that the FBI would “scour and report out every accusation,” too, but it appears that's what is happening. The bureau might ultimately conclude that this Breitbart production is insignificant or overhyped, but its decision to investigate seems less surprising when you remember that leading newspapers did the same thing.