They couldnt get him on murder for hire because there was nothing there, and at least or or 2 of the agents that was after him were also convicted for good reason. The government doesnt just not prosecute you on something just because theyve already got you, they would have hit him with the broadside of the book if they were capable. The judgement against him literally cited his political leanings as justification for his sentence too, hes locked away for forever because they dont like people believing in freedom.