Could a single hacker crash a country's network?

What does it take to cripple a nation? Someone with solid computer skills, for a start. Nefarious hackers wield a lot of power with a few keystrokes, and the United States is taking action.

Could a single hacker crash a country's network?

Backlink: http://feeds.howstuffworks.com/~r/DailyStuff/~3/sNDVgWlzFDw/hacker-crash-country-network.htm