Why Aren't The Oil Companies Drilling On Land Where They Already Hold Leases?

This is the question the Democrats who oppose off shore and Alaska drilling keep throwing back in the faces of those who are saying it's time to release the restrictions and start drilling.
One of the problems is that the oil companies have to pay heavy drilling fees to state and/or federal government for any oil that is drilled in the US. They don't have to pay those fees for oil that is imported from other companies. This makes it cheaper to buy the oil and import it rather than to drill for it here. Boy is that stupid!
But the other issue is that the land granted to them is under a lease that expires in the near future. Until recently, this drilling was not necessary because oil was less than $40 a barrell. Now that it is over $200 a barrel, they do need to drill, but the lease on that land is expiring soon. So the oil companies are not developing the land in fear that it may be illegal to drill there once the lease expires. In the meantime we'll continue to be dependent and held hostage by the Middle East countries. So go ahead and extend the leases! While everyone is pointing fingers at each other, prices continue to creep up. I think the US should start tapping into the the oil in Iraq and call it payback.