Big difference between "overlighting" and being in the dark. I will certainly agree there are many places where lighting could be cut back with no appreciable loss of security.
You keep mentioning foreign oil. How do you figure using less electricity saves much oil? My power supplier is Duke Energy, one of the largest in the US. They also supply power in South America. They generate electricity from nuclear, coal-fired, oil- and natural gas-fired, and hydroelectric power plants. Cutting off some lights, even across the country, will have only a very tiny impact in oil usage I would think. Energy efficiency of any sort is good, but I think other big changes will need to be made to reduce and/or eliminate foreign oil dependence. The biggest will be drilling for our own oil.
The energy web spans the globe and when you shut off 500,000 lights for a year the impact is significant. I don't have exact numbers, but generating electricity requires consumption of its share of hydrocarbons that can serve diverse and alternative uses. I live near a small city that uses coal -- coal can also be used to produce diesel fuel and natural gas. Easy and immediate cuts in consumption will allow time to build more nuclear and develop more domestic oil in Alaska, which of course won't happen with the Rats in power.