A Second Cold War, although not inevitable, would likely have important differences and similarities with the First if it were to occur. The main opponents are likely the same, but the relationships within the opposing sides will surely be different. The main continuity is the mobilization of the United States, which because of the First Cold War has large standing forces, a global presence, and a technology development system focused on maintaining American military dominance. Challenging Pax Americana will require the East in a new contest to agree on a new hierarchy, develop expeditionary forces, and match the military innovation capabilities of the United States. All difficult tasks.