How much did the FBI rely on a discredited Trump-Russia dossier?

The public knows that the FBI relied extensively on the Democratic Party-financed dossier, whose list of anti-Trump allegations influenced the bureau’s overall attitude toward the candidate and eventual president.

Now, Attorney General William P. Barr has made it clear he wants to know more: Just how far did the discredited dossier take the FBI into the depths of a nearly three-year Trump investigation?

“What were the standards that were applied? What was the evidence?” Mr. Barr told CBS News, adding that his focus is not on the rank-and-file but on...