Is the media required to wait until everyone has voted before calling a state?

[jberryhill]

14. Because they are looking at key counties

You can easily project a state based on a few precincts.

Consider - if I told you that Georgia, South Carolina, and Tennessee had gone for Obama, could you call the national race? Absolutely you could. Since those are cherry red states, it's not as if you'd need to know how New York and California went.

You can do the same thing internally in states. If you have enough counties in Ohio, but are waiting on, say, Cincinatti and Cleveland, you don't need to sit around and wait to find out if Obama won those cities.