Chavez Makes Threats and Plans Crooked Elections

"Chavez told a crowd gathered in the center of Caracas that if the referendum was approved and the result was questioned -- "if the 'yes' vote wins on Sunday and the Venezuelan oligarchy, playing the [U.S.] empire's game, comes with their little stories of fraud" -- then he would order oil shipments to the United States halted Monday."

More at:

http://www.cnn.com/2007/WORLD/americas/11/30/venezuela.protest/

I keep seeing these movies about how hackers can shut down computer networks, power plants, financial operations etc.

Why don't we do that against enemies like Chavez?