How does the American Revolution and the American people appear in Rip Van Winkle? How do we learn history from fiction, and how does fiction reshape history?

One of the points of "Rip Van Winkle" is to contrast the old, lazy, apathetic mindset of America under British rule with the vigor, enthusiasm and energy of the newly independent United States. Rip is a representative of the old way of thinking: he is happy to be under the rule of King George III, doesn't work hard, and doesn't have much interest in bettering himself.
After he awakes from his twenty years of sleep, he discovers a whole new world in his once sleepy village:

The very character of the people seemed changed. There was a busy, bustling, disputatious tone about it, instead of the accustomed phlegm and drowsy tranquillity. ... a lean, bilious-looking fellow, with his pockets full of handbills, was haranguing vehemently about rights of citizens—elections—members of Congress—liberty—Bunker’s hill—heroes of seventy-six—and other words, which were a perfect Babylonish jargon to the bewildered Van Winkle.

The town has gone from apathetic to alive. People, on fire about an upcoming election, question Rip as to whether he is "Federal or Democrat." Suddenly, politics matter, and people want to do more than discuss old news. They are actual participants in their own governance.
In reading the story, we learn that history changed during a twenty year period while Rip slept: The thirteen British colonies achieved their independence and formed a republic. But the story also shapes history: independence is not presented as a value-neutral change. In depicting, in an exaggerated way, the transformation of a village from apathy to energy, Irving participates in creating an American mythology: independence has wrought self-sufficiency and great positive changes in average people. Clearly, the American people were, on the whole, vigorous and energetic before the Revolution (or they wouldn't have survived in a hostile land), but Irving's story highlights and helps form a new spirit of national optimism.