In their tear-gassed standoffs with police in Ferguson, Missouri, some protesters have retaliated with that centuries-old weapon of urban revolutionaries and improvisational militaries alike: the Molotov cocktail.

Easy and cheap to make, the Molotov cocktail is thought to have been invented during the Spanish Civil War, where it was used by the Republicans against Nationalist tanks. The original design was a mixture of tar, ethanol, and gasoline in a beer bottle, creating a substance that's both sticky and flammable; either an oil-soaked rag or a long, wind-proof match is inserted into the bottle’s mouth to act as a wick. When the "bottle bomb" hits its target, the sticky mixture of fuel and flame ignite, causing a large fireball and coating whatever it hits with fire.

But why is the weapon named after Vyacheslav Molotov, the Soviet foreign minister who signed the secret 1939 Nazi-Soviet non-aggression pact that heralded World War Two?

The answer comes from Finland.

The Molotov-Ribbentrop pact divvied Europe up into “spheres of influence,” carving Poland into Nazi and Soviet territory, while ceding Finland to the Soviets, who had previously controlled it under the Russian Empire.

In the winter of 1939, after seizing eastern Poland and leaving the country’s west to the Third Reich, the Soviets invaded Finland. Molotov (“Hammer” in Russian) then said in a speech, “Tomorrow we will dine in Helsinki!” After Soviet bombs began to fall on Finnish troops, Molotov insisted that the Soviets were dropping food and drink instead. Exhibiting a keen wit, the Finns thus dubbed Soviet cluster bombs “Molotov bread baskets” (the food) and named the improvised weapons that they were using against Soviet armor “Molotov cocktails" (the drink).

The Finnish Alko corporation, a liquor conglomerate, mass-produced 450,000 Molotov cocktails during the war. The weapon proved instrumental in halting the Soviet advance toward the Finnish capital. The use of Molotov cocktails spread during the war, among Allied and Axis forces alike. In 1940, as Nazis threatened to invade the United Kingdom, the British armed home guard units with the weapon as a form of civil defense.

So Molotov, the war-mongering Bolshevik, ended up lending his name to a bomb known for its popularity in anti-Communist protests behind the Iron Curtain.

Fast forward to today in the United States. The Bureau of Alcohol, Tobacco, and Firearms considers Molotov cocktails a “destructive device” under the National Firearms Act. This does not mean that the weapon is banned—only that you must register your Molotov cocktail with the ATF.

Of course, you will be prosecuted for hurling one at a police car.

This article originally published at The New Republic here