In the silo, two soldiers each have to turn a key at the same time to get the launch sequence going. The keys are physically separated so no one person can create nuclear chaos. Senior managers at highly networked organizations are no longer in charge the way they once were. Individuals way down the totem pole of management can single-handedly determine the functionality or survivability of the network. The techie who knows how to tweak the bits, manage the complex graphical user interface screens and interpret policy for implementation is the real powerhouse.
Network administrators determine who has access to network resources from beyond the perimeter.
They control which insiders have access to which internal resources - a fairly critical decision because we don't always know the intentions and motivations of everyone in our employ. They handle the configuration of the network nexus points such as firewalls, routers and servers. And they can bring a network up or down depending on its operational needs, maintenance or upgrading, following corporate policy when under attack - or based on their own whim. Many security decisions affect the company's ability to do business. You need to decide whether putting that authority into the hands of one person who may be a new employee, a marginally competent worker or a staff member with questionable loyalty is a smart thing to do.