Or that he was shot by Boston Corbett to cover up any complicity by the radical Republicans. Its been a long time since I read or saw anything about this but I recall an interesting tv special about it back around 1980 that aired, claimed the radicals were involved. I have always found it suspicious that Corbett, a supposedly crazy man, shot Booth in a barn on fire.
IMO, there was plenty of motive on the part of the radicals to wish Lincoln dead; fire up the North, end the easy reconstruction Lincoln had in mind, or deportation of the ex slaves etc.