Has World War III begun?

American missiles fired by Ukraine into Russian territory, a new Russian hypersonic ballistic missile used against Ukraine, the threshold for the use of atomic weapons lowered by Vladimir Putin, North Korean contingents reinforcing their presence in Russia, and Europeans preparing for the worst: faced with the prospect of American disengagement, the conflict between Moscow and Kiev is escalating. How far should we fear this brutal escalation? To what extent is this war already global?