Alot of liberals want energy independence. I am one of them, and it is one of my top priorities. When I decided to get behind oil drilling, it was with the full knowledge that someday, somewhere there would be a spill. We just can't do it right 100% of the time with this stuff, since there are just too many variables.
Well, the spill came sooner rather than later, unfortunately.
Now, we'll be that much more entrenched into having to defend the Middle East for the next 50 years from increasingly greedy powers. Mark my words, eventually they will come for the oil. The less we drill, here, the more we'll have to defend there.