Original: Lincoln 's assassin , actor and Confederate sympathizer John Wilkes Booth , had also plotted with fellow conspirators , Lewis Powell and George Atzerodt to kill William H. Seward ( then Secretary of State ) and Vice President Andrew Johnson respectively .
Simplified: Lincoln 's killer , John Wilkes Booth , was an actor and Confederate sympathizer who had plotted with other men to kill the Secretary of State , William Seward and the Vice President Andrew Johnson .