Joe Scarborough has denied having it in for Marco Rubio. But on today's Morning Joe, he went on an anti-Rubio rant so protracted that one segment wasn't enough to contain it. Scarborough first called Rubio the "Republican Obama," who's been marketed like a "bag of potato chips," and the "emptiest suit" in the campaign. After a commercial break, Scarborough hectored Rick Santorum, who has just endorsed Rubio, repeatedly challenging him to name Rubio's accomplishments. By all means, let's carefully examine the record of all candidates. But for Scarborough to deny that, for whatever reason, he has a grudge against Rubio...