Why oil?

What seems dumb to me, is that we're wasting money on oil, whereas we could focus more on more renewable sources. The money we're spending on OTHER COUNTRIES could be focused domestically on energy sources like solar and or wind energy. In fact, we could build a light rail system that would work instead of going to war. Maybe it's because I'm an isolationalist, but I think the money being wasted on this situation has some real purposes hear.