A key reason the protests against the war in Vietnam were so much more potent than against the war in Iraq is that there was a draft back then.

Millions of young people lived in fear that they — or someone they loved — would have their number called, and they’d be shipped off against their will to the rice paddies and jungles of a faraway land for a cause they felt was unjust and futile. From 1964 to 1973, the U.S. military conscripted 2.2 million men — boys, really — out of an eligible pool of 27 million. This helped fuel the mass movement against the war.

Young people today aren’t worried about being drafted to fight Kim Jong Un in North Korea. But many are palpably concerned that they or someone they know could get shot at school. High-profile incidents, culminating with last month’s shooting in Parkland, Fla., have shaken many middle-class kids, who would not otherwise be inclined to activism, out of their suburban comfort zones.