Government de facto. A government of fact. A government actually exercising power and control, as opposed to the true and lawful government; a government not established according to the constitution of the nation, or not lawfully entitled to recognition or supremacy, but which has nevertheless supplanted or displaced the government de jure. A government deemed unlawful, or deemed wrongful or unjust, which, nevertheless, receives presently habitual obedience from the bulk of the community.

There are several degrees of what is called “de facto government.” Such a government, in its highest degree, assumes a character very closely resembling that of a lawful government. This is when the usurping government expels the regular authorities from their customary seats and functions, and establishes itself in their place, and so becomes the actual government of a country. The distinguishing characteristic of such a government is that adherents to it in war against the government de jure do not incur the penalties of treason; and, under certain limitations, obligations assumed by it in behalf of the country or otherwise will, in general, be respected by the government de jure when restored. Such a government might be more aptly denominated a “government of paramount force,” being maintained by active military power against the rightful authority of an established and lawful government; and obeyed in civil matters by private citizens. They are usually administered directly by military authority, but they may be administered, also, by civil authority, supported more or less by military force. Thorington v. Smith, 75 U.S. (8 Wall.) 1, 19 L.Ed. 361.

De facto government. One that maintains itself by a display of force against the will of the rightful legal government and is successful, at least temporarily, in overturning the institutions of the rightful legal government by setting up its own in lieu thereof. Wortham v. Walker, 133 Tex. 255, 128 S.W.2d 1138, 1145.

Government de jure. A government of right; the true and lawful government; a government established according to the constitution of the nation, and lawfully entitled to recognition and supremacy and the administration of the nation, but which is actually cut off from power or control. A government deemed lawful, or deemed rightful or just, which, nevertheless, has been supplanted or displaced; that is to say, which receives not presently (although it received formerly) habitual obedience from the bulk of the community.

De jure. Descriptive of a condition in which there has been total compliance with all requirements of law. Of right; legitimate; lawful; by right and just title. In this sense it is the contrary of de facto (q.v.). It may also be contrasted with de gratia, in which case it means “as a matter of right,” as de gratia means “by grace or favor.” Again it may be contrasted with de aequitate; here meaning “by law,” as the latter means “by equity.”

Source:

Black’s Law Dictionary, Sixth Edition (With Pronunciations)