Because the people have ultimate power (popular soverignty), the power of the government is naturally granted. How is this achieved?

Through a granted power. Popular sovereignty is a doctrine rooted in the belief that every human being is sovereign, and rather than a monarch or single individual, that they could unite and each delegate a small portion of their sovereign powers and duties to those who wished to temporarily serve as officers and employees of a state, who would then serve the rest of the people according to the will of the people expressed via a constitution and democratic process. That the people fought for equality with the King of England was enshrined in their Declaration of Independence and was a matter of common knowledge in America after the Revolution. The first Chief Justice, John Jay, published this in his Opinion in the first major supreme Court case in order to briefly illustrate what was ordained and established and would eventually come to be known by the American usage of the term "popular sovereignty": It will be sufficient to observe briefly that the sovereignties in Europe, and particularly in England, exist on feudal principles. That system considers the Prince as the sovereign, and the people as his subjects; it regards his person as the object of allegiance, and excludes the idea of his being on an equal footing with a subject, either in a court of justice or elsewhere ... No such ideas obtain here; at the Revolution, the sovereignty devolved on the people, and they are truly the sovereigns of the country, but they are sovereigns without subjects, and have none to govern but themselves