Franz Ferdinand was shot by Austrian citizen.
Austria wanted to go to war against serbia long time before that.
Lincoln was shot by an American citizen, but he wasn’t on the payroll of Gen Lee or Virginia.
Austria Hungary resisted all provocations until Germany reacted forcibly to the 9/11 style attack upon the heart of European governance, as the black hand had calculated
Austria wanted to go to war so badly they offered Serbia ridiculously prohibitive terms & after Serbia accepted declared war on them anyway.