Recently a number of liberal political theorists, including Rawls and Walzer, have argued for a ‘supreme emergency exemption’ from the traditional just war principle of discrimination which absolutely prohibits direct attacks against innocent civilians, claiming that a political community threatened with destruction may deliberately target innocents in order to save itself. I argue that this ‘supreme emergency exemption’ implies that individuals too may kill innocents in supreme emergencies. This is a significant theoretical cost. While it will not constitute a decisive refutation of all arguments for a supreme emergency exemption, my hope is that many will see this cost of endorsing the exemption as unacceptable