"As a prosecutor, you build a case by having your cooperating accomplice witnesses plead guilty to the big scheme you are trying to pin on the main culprit."

"After all, what makes these witnesses accomplices, literally, is that they were participants in the main culprit’s crime. That’s the scheme you’re trying to prove. So, on guilty-plea day, the cooperator comes into court and admits guilt to the same conspiracy on which you are trying to nail the lead defendant. That gets you 90 percent of the way home.... This kind of guilty plea signals to the world, including to all the other suspects, that the accomplice is ready to testify that the criminal scheme existed — it is not a figment of the prosecutor’s fevered imagination.... With respect to the president and 'collusion,' Mueller does not have a crime he is investigating. He is investigating in hopes of finding a crime, which is a day-and-night different thing. The lack of a crime means the 'accomplices' are not really accomplices....  [I]f you turn a prosecutor loose to investigate political campaign activities — you are apt to find unsavory conduct that is not criminal but that some people will lie about.... But the convictions [Mueller] has amassed, even if they are only for false statements or are otherwise unrelated to the Trump-Russia rationale for the investigation, prove that many people Trump brought into his campaign were corruptible and of low character...."

Writes Andrew McCarthy (National Review).