traditional Chinese concept of legitimacy used to support the rule of the kings of the Zhou Dynasty and later the Emperors of China. Heaven would bless the authority of a just ruler, but Heaven would be displeased with an unwise ruler and give the Mandate to someone else.Since that time, Americans have used that word to justify changing the executive branch, if necessary, by force. This is contrary to our American system - unlike the Chinese system (and most other political systems on the planet), we regularly change governmental horses. We don't have to find some astrological portents to signal that a change is needed. Every 2-4 years, we get a chance to voice our dissatisfaction with the people in charge.
The Mandate has no time limitations, but a performance standard.
In the American system, revolution is seldom needed or justified. Use of this inappropriate and dumb term should be eliminated in America. Save its use for those political systems in which the people have no way to change their leadership.
Like Saudi Arabia. Or Iran. Or Cuba.