After the first year or two of reconstruction, the Leagues in the larger Northern cities began to grow away from the strictly political Union League of America and tended to become mere social clubs for members of the same political belief.

The eminently respectable Philadelphia and New York clubs had little in common with the leagues of the Southern and Border States except a general adherence to the radical program.
Even before the end of the war the League was extending its organization into the parts of the Confederacy held by the Federal forces, admitting to membership the army officers and the leading Unionists, though maintaining for the sake of the latter "a discreet secrecy." With the close of the war and the establishment of army posts over the South, the League grew rapidly.

The civilians who followed the army, the Bureau agents, the missionaries, and the Northern teachers formed one class of membership; and the loyalists of the hill and mountain country, who had become disaffected toward the Confederate administration and had formed such orders as the Heroes of America, the Red String Band, and the Peace Society, formed another class.

Soon there were added to these the deserters, a few old line Whigs who intensely disliked the Democrats, and others who decided to cast their lot with the victors.

The disaffected politicians of the up-country, who wanted to be cared for in the reconstruction, saw in the organization a means of dislodging from power the political leaders of the low country.