Excellent analysis, LW.

It's true that Rocco, with a bum leg, would never be able to escape, and that a dead Rocco would tell no tales. But, while Michael could not have been charged directly in Roth's murder, the FBI would have descended on Michael because of Rocco's connection to him, and the sensational murder of Roth would have played huge in the media. Media coverage would have resurfaced all the charges against Michael raised in the Senate hearings, and have damaged Michael's "legitimate" front once again.