I think that the supply problems in China were primarily related to price controls. In regard to shortages elsewhere, I think that it is simply demand destruction progressively moving up the food chain.

Let's assume a geometric progression in crude: $50, $100, $200, $400 . .

This results in a geometric progression in gasoline: $2, $4, $8, $16. . .

As (IMO), net oil exports decline, the refiners in importing countries are caught between these two geometric progressions. They have to balance higher crude oil prices against the declining number of consumers who can and will pay the higher product prices.

With continuing apologies to several literary figures:

"Ask not for whom forced conservation comes, it comes for thee."

We're building inventory for a number of reasons:

1. We are paying, in many cases, the highest price for the highest volume. Since we buy the most oil, and we're willing to spend an arm and a leg for it we can still snatch up sellers at the expense of most other countries.

2. We have energy security arrangements with countries like Canada, Mexico, Iraq, and even Saudi Arabia which obligate them to ship to us.

3. Iraq. We have hegemony over Iraqi oil supply.

4. Shipping lanes. We control and secure many of the world's oil shipping lanes. It's not that we take the oil so much as we ensure safe passage to and from US ports. It makes it easy for many countries to ship here.

5. Heavy Oil. The US still has the largest heavy oil refining capacity in the world. So much of it can come to us where it still has difficulty finding other markets.

6. Military presence in the world's oil producing regions. We have limited but substantial influence over the world's oil supplies due to our military presence in many of the world's largest oil producing regions. According to the Carter doctrine, the US would go to war to secure oil supplies in a pinch. Many countries have decided it is better to make a fortune on the US demand for oil than to invoke the US's anger and risk becoming the next Iraq. On the other hand, countries like Iran and Venezuela have made policy out of visibly opposing US oil hegemony. On the one hand, Iran suffers from sanctions. On the other, Venezuela enjoys status as a top exporter to the US.

7. The tough Irony is that all major oil exporting countries are to some degree dependent upon US demand. Even with a rising China, it is unclear if Chinese demand at the expense of US demand could result in the same beneficial relationships many exporters have seen. The status quo is also very powerful in this regard.

8. Most oil still trades in US dollars. This results in the US still having a lever to influence the flow of world oil supplies. Despite the moves by many countries, shifting reserve currency takes time and money.

9. Food exports. The US exports food to most oil producing countries who must import food. Food is becoming a more potent lever for trade in a food constricted world. Food for oil is not explicit but becomes implicit if you look at trade relationships like Angola and Iraq.

In all, the US is still a very powerful economic player on the world scene and has many options to ensure its energy security.