But it hasn’t happened this time: all through the period of the alleged bubble, inventories have remained at more or less normal levels. This tells us that the rise in oil prices isn’t the result of runaway speculation; it’s the result of fundamental factors, mainly the growing difficulty of finding oil and the rapid growth of emerging economies like China. The rise in oil prices these past few years had to happen to keep demand growth from exceeding supply growth.

Saying that high-priced oil isn’t a bubble doesn’t mean that oil prices will never decline. I wouldn’t be shocked if a pullback in demand, driven by delayed effects of high prices, sends the price of crude back below $100 for a while. But it does mean that speculators aren’t at the heart of the story.

Why, then, do we keep hearing assertions that they are?

Part of the answer may be the undoubted fact that many people are now investing in oil futures  which feeds suspicion that speculators are running the show, even though there’s no good evidence that prices have gotten out of line.

But there’s also a political component.

Traditionally, denunciations of speculators come from the left of the political spectrum. In the case of oil prices, however, the most vociferous proponents of the view that it’s all the speculators’ fault have been conservatives  people whom you wouldn’t normally expect to see warning about the nefarious activities of investment banks and hedge funds.

The explanation of this seeming paradox is that wishful thinking has trumped pro-market ideology.

After all, a realistic view of what’s happened over the past few years suggests that we’re heading into an era of increasingly scarce, costly oil.

The consequences of that scarcity probably won’t be apocalyptic: France consumes only half as much oil per capita as America, yet the last time I looked, Paris wasn’t a howling wasteland. But the odds are that we’re looking at a future in which energy conservation becomes increasingly important, in which many people may even  gasp  take public transit to work.