What today's guilty plea in the Russia probe shows (and what it doesn't)

(CNN) -- For months and months, Republicans -- led by President Donald Trump -- have pointed to an ongoing probe into the origins of the FBI's counterintelligence Russia meddling investigation as the smoking gun of the 2020 (and 2016) election.

Of John Durham, the Connecticut US Attorney tasked by Attorney General William Barr with overseeing the probe, Trump said Thursday: "I hope he's doing a great job. And I hope they're not going to be politically correct and I hope they do what -- because the fact this was President Obama knew everything, Vice President Biden, as dumb as he may be, he knew everything and everybody else knew everything."
Trump went on to call the alleged mishandling of the FBI investigation the "greatest political crime in the history of our country."