The second benefit would presumably be national security. The idea is that we could use offshore oil to reduce our dependence on foreign oil. For example, we could reduce our troop presence in the Middle East if we no longer considered Middle Eastern oil essential to our economy. The problem with this benefit is that its probability is very low. As mentioned above, assuming we were able to get all of the oil off our shores it would only last us 11 years. Assuming we planned on living past 11 years, we would still need to rely on other sources for our oil consumption. Put simply, the amount of oil offshore is a drop in the bucket of the overall world supply.