A
Lafayette Foster becomes Acting President. Since the assassination occurs after Lee's surrender, I doubt that Johnson's death will have much of an impact on the war itself, fantasies of a resumed guerrilla war notwithstanding. Foster, as a Republican, isn't going to govern exactly as Johnson did while he is in office. But considering how he lost office in 1866, and later became a Democrat, I think that there will be similarities. I think Foster will be a bit more lenient towards the South than the radicals would want. It's almost a moot point, seeing as Foster will only be in office until March 4th 1866. Succession law at the time demanded another Presidential election under the circumstances presented here. So, there's an election in 1865. Either William Seward or General Ulysses Grant becomes President beginning in 1866. While the absence of Johnson might be a boon to reconstruction efforts between 1866 and 1869, the overall effect might end up slightly worse than OTL, or else not too different. For the moment let's presume Grant wins in 1865, and governs more or less as he historically did. The radicals will certainly be happier than they were, but then again, they don't have Andrew Johnson to compare him to so I don't know what the radical attitude towards President Grant would be. He's probably reelected in 1869. And here we get to the problem as far as reconstruction is concerned. In my humble opinion, there is a distinct possibility of a Democratic, or Liberal Republican, victory in the election of 1873. So, we might see the end of the Southern Occupation years before it occurred historically.