Even that is oversimplified. To launch nuclear-armed ICBMs, it takes to subjects to turn two keys separated by sufficient distance that no one person can turn b

Even that is oversimplified. To launch nuclear-armed ICBMs, it takes to subjects to turn two keys separated by sufficient distance that no one person can turn both keys at the same time. In many cases, specially involving sysadmins, you want a quorum so a rogue sysadmin cannot lock others out or commit other destructive actions.