Even by the gruesome standards of World War I, April 22, 1915, was ghastly. On that day, Germany unveiled a weapon it had been working on for years - chlorine gas. Soon after its release, French soldiers began choking.

The Allied line "was absolutely covered with bodies of gassed men", British soldier Lendon Payne told the Week. "Must have been over 1000 of them." Thus launched "the chemist's war", a scramble to meet horror with horror.

By the end of World War I, more than 90,000 soldiers had been killed by poison gas - many after weeks of agony. A million more men had been blinded or injured for life.

By 1925, the League of Nations had drafted a treaty to ban the use of such gas during war.


Most countries signed. Even those who didn't (during the Cold War, the United States and Soviet Union built out their own stockpiles) adhered to the general principle: that chemical weapons have no place in war.

But over the past century, a handful of rogue trouble spots have deployed chemical weapons. And while this tactic often brings swift, international condemnation, there's rarely much lasting punishment.

Benito Mussolini dropped mustard-gas bombs in Ethiopia, the US used Agent Orange during the Vietnam War, Egypt used mustard gas and a nerve agent in Yemen, and in 1985, Iraq used an array of chemical weapons against Iran, with President Ronald Reagan's approval.

The next year, Saddam Hussein, then a US ally, attacked his country's Kurdish minority with gas.

Now world leaders are calling for action over the use of gas in Syria. Will anything actually come from all this? If history is our guide, probably not.