Dramatic irony creates tension when Rip returns to town after his long nap in the Catskills:
The appearance of Rip, with his long, grizzled beard, his rusty fowling piece, his uncouth dress, and an army of women and children at his heels, soon attracted the attention of the tavern politicians [...] The orator bustled up to him and, drawing him partly aside, inquired “on which side he voted?” Rip stared in vacant stupidity.
Only the reader, not Rip or the townspeople, knows what is going on. Rip looks like a stranger because no one has seen him for 20 years, even if it feels like only a short time to Rip. In those 20 years, everything and nothing has changed. Politics were always a topic of conversation among neighbors in the inn, but the revolution has made it even more important for people to declare "sides" so their neighbors know how to talk to them. The question of which side Rip votes on means everything to the "tavern politicians" because brand new American political parties have formed while Rip was asleep. To Rip, meanwhile, post-Revolutionary politics don't mean anything. As far as he is concerned, he is simply talking to his neighbors. Only the reader, who has seen history and the folktale alike unfold, understands both sides of the interaction.
The reader's ability to hold both political realities in this moment is part of Irving's Romanticism. Irving, like other Romanticists, idealized the past and lamented that the modern world would never be what it once was. Far from giving up on the past, Irving and other Romanticists looked for ways art and writing might help bring pieces of the past into the present as it continued hurtling toward the future. This instance of dramatic irony places the reader of "Rip Van Winkle" in the ideal position according to Irving's Romanticism: anyone who reads the story is free to nostalgically and idly embrace the past Rip represents without denying the reality of post-revolutionary politics.