We get 8% of our oil from Saudi Arabia
That's a lot of oil, but there are other sources that could replace it, such as Russia, as well as increased domestic production. If push comes to shove, we could live without Saudi oil. The Saudis know this, too.
The reason why people in so many other countries pay $4 or more per gallon is mostly due to excessive taxation by their governments. Their oil companies pay the same per barrel as ours. It's possible they might have higher refinery costs due to economies of scale or stricter environmental regulation, but the overwhelming reason for their high prices is higher gasoline taxes.