Second American Revolution is the event in the Wolfenstein II: The New Colossus that involves BJ and the entire American Resistance network to rise up against the Nazis to liberate the American Territories from their oppressive rule.
After the Nazi forces came to the United States after dropping the atom bomb on New York City, the United States surrendered and pleaded with the American citizens and its military to step down from fighting and cooperated with the Nazi regime. However, the order of surrender fell unto the deaf ears of some of US people and military personnel as Americans like Grace Walker, Horton Boone, Joseph Stallion's father and remnant of U.S. military personnel like Captain Gerald Wilkins raised their gun at the Nazis, causing huge trouble for the Nazi regime to pacify the American Territories. Their resistance was eventually crushed by the arrival of the Ausmerzer, making the entire American Resistance network to scatter across the country. As the result, the Nazis managed to pacify the American Territories and marked the event as Liberation Day.
The arrival of B.J. and the Kreisau Circle changed the tide of the war in the favor of the American Resistance Network as B.J. managed to destroy the Oberkommando HQ in Roswell with a nuclear warhead and managed to get to Horton Boone to get the connection of the scattered American Resistance together.
After the capture of the Ausmerzer, B.J. and his group assassinate Irene Engel on live television with Grace Walker (or Probst Wyatt III, depends on timeline) declaring their uprising to the rest of the American Territories making the Second American Revolution a reality as hundreds of uprisings erupt across America as the grip of the Nazi regime crumbles. Furthermore, B.J.’s assassinations of all 16 Übercommanders caused the total collapse of the chain of commands of Nazi forces in the territories. As a result of these events and the quick gains by the American Resistance, the puppet government collapsed and the American people soon liberated the country from Nazi rule ending their oppressive occupation after 12 years.