We have. Even before the insane Santa Barbara oil spill motivated ban on off shore drilling, we still had to import.
We have not!!! Everytime we find possible oil reserves it is put off limits. Vast oil, coal and natural reserves are available within our own boundries and we cannot get to it because of politics. Rules, regulations and government ineptness and pandering prohibits new cost effective refineries from being built and yet we complain at the price of diesel. New nuclear power plants are prohibited for the sake of politics in many parts of the US. It is insane to defend our national energy policies!!