All of the mentioned leaders had a divided nation under different circumstances. However, they intelligently crafted their speeches in order to appeal to peoples sentiments and focused on the union that all citizens must have during difficult times.
Lincoln appealed to the promise of a nation where all men are free in his Gettysburg Address. Woodrow Wilson made it clear that the American citizens must unite against the global threat that represented the Nazi invasion of Europe. John Adams, which was highly supportive of a strong federalist government, also made it clear that it was in the best interest of all American people to have a Central Government who could manage the nation's affairs in a better way.
