Answer:
the formal tone and the description of the crowd waving flags and singing patriotic songs.
Step-by-step explanation:
The formal tone used in this passage, along with the description of the crowd waving flags and singing patriotic songs refine the central idea that the resignation of the President is a historical event. If the event was common, or expected, then it is unlikely that people would have gathered in such great displays of patriotism. Moreover, the formal tone of the passage contributes to the idea that the event is something that deserved solemnity.