Here we are going to look at the best available figures for offshore drilling, specifically the areas that are currently off-limits. That's what the fight is about.

First, how much oil we consume and how much we "produce":

The bottom line is that we consume a heck-of-a-lot more, close to twice what we currently produce.

And how much more could we get "offshore" from areas that are currently off-limits? Well if you comb all the literature out there, the simple answer is that we don't really know. Here's the closest that I've been able to get from an article in Scientific American:

The Minerals Management Service (MMS), part of the U.S. Department of the Interior responsible for leasing tracts to oil and gas companies and collecting the royalties on them ... has estimated that there are around 18 billion barrels in the underwater areas now off-limits to drilling. That's significantly less than in oil fields open for business in the Gulf of Mexico, coastal Alaska and off the coast of southern California, where there are 10.1 billion barrels of known oil reserves as well as an estimated 85.9 billion more.

So the whole fight is for 18 billion barrels (as far as we know). To place this figure into context, the current estimated reserves for the US (excluding all offshore) is about 22 billion barrels. Add 96 billion barrels from the current offshore drilling areas (total now up to 118 billion barrels) and those 18 billion barrels don't seem like so much. Let's look at the world's oil reserves and consumption rates and compare all these numbers:

*Decade numbers = Per Year figures x 10

Note that by 2030, oil consumption is estimated to go way up due in large part to China and India. You'll also notice that the amount of oil in these offshore off-limit areas are likely to be negligible in the long run. Fully exploring the areas that we currently drill will likely produce far more oil. Opening the off-limit areas will not affect the world supply and will certainly have little effect on the price of gas. But it will line the pockets of anyone who can drill. Remember the price of gas is largely dictated by world supply and world demand - the notion that the US is an insulated market is hogwash. So why would John McCain and the GOP support such a measure?

Sources: Energy Supply page on the Global Education Project, The Energy Information Administration, The Minerals Management Service, The CIA Factbook.