There has been no occasion for the active exercise by Congress of the power to guarantee a republican form of government in any state save in those cases where the existing state governments were overthrown as the result of the rebellion of the Southern states in 1861 and the attempt by the people of those states to form a new federal government under the name of the Confederate States of America. This attempt was so far successful that in eleven Southern states the regularly constituted state governments ceased to exist and revolutionary governments were substituted. These new state governments were de facto governments and were republican in form; but they were not the state governments recognized by the federal constitution, for they were not organized to exercise powers which states might have under that constitution, but were, on the other hand, organized to exercise power in hostility to the government therein provided for.

The people of the Southern states in rebellion continued to be citizens of the United States and subject to the constitution and laws of the United States and the authority provided under such constitution and laws; but ceasing for the time being to exercise the political functions provided for by the federal constitution they were without "state" governments in the sense of the federal constitution. Therefore, as far as the federal government was concerned, those states at the end of the war were still without state governments. It thereupon became the duty of the federal government, as soon as peace and tranquillity had been so far restored in those states as to make civil government possible, to provide for the establishment therein of regular state governments; and this was done under the provisions of the so-called reconstruction acts (1867).

It is unnecessary now to discuss at length the provisions of these acts or to consider the different questions which arose under them; it is enough to say that state governments of a republican form were re-established. During the interval between the overthrow of the existing but irregular state governments and the recognition of new state governments under the reconstruction acts, the states whose people were in rebellion did not cease to be states in the Union, but they were for the time being states without any regular and lawful governments, that is, without any governments which the federal government could recognize.