Who’s panicked by the thought of oil at $100 a barrel?

George W. Bush clearly. How else can one explain the president’s decision, odd in a markets-oriented administration, to sic the Justice Department on oil companies.

One reason Bush is reacting may be that he has been talking more to his father lately, as well as his dad’s favorite old adviser, James Baker.

Calling dad is what people do when they panic, even presidents. And when opinion polls look bad, as the Republicans’ do, the urge to phone home probably gets stronger. In the case of oil, advice from that generation of Texan guys may not be so useful. Consider the differences between this economy and its predecessors.

Back in the old days, oil prices mattered for four reasons. The first was that oil was the lifeblood of industrial economies. The second was that even citizens of developed countries didn’t have a lot of disposable income. The third was that economies were so regulated that they had a hard time shifting after shocks. The fourth was cultural: countries like the U.S., Germany, and Japan didn’t believe that sustained growth was possible in anything but a smoke-and-oil economy.

The evidence seemed to bear this out: post-World War II consumption of petroleum product grew at an average annual rate of 4.5 percent, faster than the growth of the economy. As Baker and Poppy learned early, America had seen the future and it was oil.

As recently as a few years ago, many economists had a rule of thumb that the U.S. economy loses a percentage point of gross domestic product growth for every $10 rise in the price of a barrel of oil.

But economies have changed. As former Federal Reserve Chairman Alan Greenspan reminded us last autumn before he retired, from 1973 on oil consumption in the U.S. grew only half a percentage point a year, much less than real GDP. By another yardstick involving absolute numbers and not growth rates, the ratio of oil-use-to-GDP narrowed by half. A range of changes, from hitech to hybrids, contributed to that shift.

Nor are we alone. Japan, which used to be the world’s second largest petro-consumer, also saw its ratio of oil-consumption-to-GDP drop by half.

It’s important to remember what every congressman and the president himself knew before their oleaginous anxiety consumed them: these days growth and high oil prices are more likely to coincide than preclude one another.

James Lucier of Prudential Equity Group notes that the Japanese stock market rose 40 percent last year, even as oil prices also rose. “Structural reform has freed the Japanese economy of its old fears,” he said. “‘Oil shokku’ used to be a phrase in Japan but you don’t hear it that much any more at dinners. You are more likely to hear ‘smaller government.'”

In other words, it is time both the president and the rest of us started treating oil like just another product with relatively inelastic demand, much like cable television or the frappuccino you get after you buy that gas.

Cable companies raise rates all the time; we pay $100 for news that we used to get free. No one has suggested that Starbucks Corp. Chairman Howard Schultz is a price gouger, even though his plain coffee – never mind his frappuccinos – costs roughly four times what we paid for something by the same name in 1982.

Even if the president will not give up his plan to drive down the price of oil, there are simpler ways to do it than manipulating the market. The best move would be to lift the 54-cent tariff on Brazilian ethanol. That’s what Brazilian Finance Minister Guido Mantega suggested this week. The move might even raise the wages of beleaguered workers who harvest Brazil’s sugar cane.

Or what about the proposal by Senator Bob Menendez, Democrat of New Jersey, that drivers get a 60-day holiday from federal taxes at the pump? That would cut the price of gas by 18 cents a gallon and the price of diesel even more.

In this election year Republicans, and not just Bush, seem to be in the mood for big-government solutions. Anyone who has ever dined in Essex County knows that it is hard to get to the left of a New Jersey Democrat.

Yet in this oil debate a figure no less than Charles Grassley of Iowa has managed to do it. The Republican Senate Finance Committee Chairman is advocating more vigorous enforcement of current law by the Internal Revenue Service. “I want to make sure the oil companies aren’t taking a speed pass by the taxman,” he said.

In the end, we can understand why lawmakers are so concerned about higher oil prices and the specter of the big $100. They are not sure that the political landscape will change in time to save them before November. But that time frame need not constrain the rest of us, who will probably still have a job after summer gas prices soar. Sure, the price of oil is high. But you always have to ask: relative to what?

Miss Shlaes is a columnist for Bloomberg News.