Each year on this day, Americans celebrate our founding principles and the birth of our nation, but in these chaotic and polarized days, it is also important to remember that the United States was born from a crisis of unity and has experienced two more at roughly 70-year intervals — the Civil War and the Great Depression. Both nearly tore us apart, yet each sparked a civic rebirth. After each great rupture, the government was restructured; each took the nation closer to its founding ideals; each brought greater liberty, justice and opportunity to expanding groups of Americans; each changed forever and for the better the relationship between government and the people.