If I recall correctly, we take about 16% of ME oil. But it's a market. You know what that means right? If a regional war broke out in the ME and oil production was impacted, that would drop supply out of the market and China and all the other countries that need oil would still need it. Price would skyrocket.
Why are we the guarantor of security in the ME? Because we inhirited that role from France and Briton after WWII.