The plot to assassinate Lincoln was part of a larger attempt by Booth and his co-conspirators that included VP Andrew Johnson and Secretary of State, William Seward. Booth obviously succeeded but Johnson's intended assassin, George Atzerodt, got cold feet and Seward's, Lewis Powell, only managed severely wound him.
What do you think would have been the results had the plan gone through and all three men were killed? At the time Presidential succession law stated that the President Pro tempore was the one would have ascended to the Presidency in the event of a dual vacancy and would also see an election called in the December of that year.
In addition, how do you think this would effect Reconstruction now that both Lincoln and Johnson are out of the picture?