I don't think anyone is arguing that it does. I think this is simply an issue of percentages, and maybe that amazing difference in those percentages is what makes an impact. 67% of ocean oil from seepage vs 1% from drilling leaks is pretty dramatic.

Absolutely... and demonstrates how well nature copes with one type of spill and not so well with the other.

And causes pregnancy

All I'm saying is that we don't have an impressive track record when it comes to getting our industrial infrastructure to coexist with natural environments. I don't have anything to back it up, I'll admit to this being conjecture, but I'd say more often that not that over the long run, presence of human-constructed and run operations in an environment does not have a positive affect on the flora and fauna. Not necessarily disastrous, and not even necessarily an impact that isn't recoverable in the even longer run. But if it's a question of "which is more likely" I fall on the side of it's more likely that a large scale drilling operation will have a net negative impact than a net neutral impact. So that, combined with the rather minuscule projected benefit to oil supply, is enough for me to prefer we just stay out of there.

Why can't the oil companies drill on the 68 million acres they already lease for drilling, but sit idle?

Don't really have a factual answer, but my initial guess would be because there isn't a sufficient supply of oil to make money by drilling there.

Then why did they spend the money to lease them?

We need to use what we have.

This just speaks volumes to the American culture. We don't want what is old and still functional when we can have new. Why use the old land, we can just drill in to new places.

This does happen in cases where it is cheaper to do something new. In this case, I don't think it applies. Believe me, to the extent that mainland oil lease lands can produce, they will be used by the leaseholders or get subleased to someone who will. It's way more expensive to build and ship from Alaska.