during the post-civil war reconstruction era, there were major disagreements on the treatment of ex-confederates and of former slaves, or freedmen. johnson broke with the radical republicans and formed a loose alliance with moderate republicans and democrats. a showdown came in the congressional elections of 1866, in which the radicals won a sweeping victory and took full control of reconstruction, passing key laws over the veto. johnson was impeached by the house, but acquitted by the senate.