In his 2015 study of Joseph Stalin, historian Stephen Kotkin suggested that the Bolshevik revolution could have been stopped by just two bullets: one aimed at Vladimir Ilyich Lenin, hiding across the border in Finland but pressing the Bolshevik Party to seize power; a second bullet for Leon Trotsky, on the ground in Petrograd as a determined band of Red Guards, sailors, and soldiers stormed the Winter Palace.

Kotkin was stressing the many contingencies which shaped the outcome. Lenin’s plan was resisted by most Bolshevik leaders. Trotsky had been aligned with the rival Mensheviks. Force of personality decided the outcome. A relentless Lenin cajoled, threatened, and pleaded until his party agreed to risk all. Ahead was a bitter civil war, but eventually a political philosophy and state built on Leninist principles.