How do McCarthy's references to Abraham Lincoln at the beginning and end of his speech support his argument?

McCarthy's references to Abraham Lincoln at the beginning and end of his speech likely serve to establish a historical and patriotic context for his argument. By invoking Lincoln, a revered figure in American history, McCarthy may be aiming to align his ideas with values associated with the former president, such as preserving the Union and defending democracy. This rhetorical strategy can lend credibility to McCarthy's argument by tapping into the audience's positive perceptions of Lincoln and the principles he represented.