In numerous unsigned editorials, The Wall Street Journal has argued that cutting the federal funds rate to 2% from 5 1/4% last September has been the main reason prices of crude oil and food commodities have soared in recent months. Such commodities are priced in dollars and the dollar was generally falling through February, though not in the past two months (even though the funds rate was reduced by one percentage point).

An April 28 editorial, “The Fed’s Bender,” notes that “since 2003 the dollar price of oil has climbed far more rapidly than the euro price — 273% in dollars, compared to 146% in euros.” It is not likely that the whole 2003–2008 picture reflects “the European Central Bank’s sounder monetary management,” as the editorial implies. The euro had dropped to below parity with dollar until late 2002. And the fed funds rate was repeatedly increased from 1% in 2003 to 5 ¼% in mid-2006 (well above the ECB’s equivalent 4% rate). The euro rose partly because it had first fallen, but also for reasons other than central bank interest rates (economists have no reliable model for forecasting floating exchange rates).

The editorial boldly concludes that “had the dollar merely retained the same purchasing power as the euro, today’s price of oil would be below $70 a barrel.” That is a counterfactual exercise that makes little sense.

Even if we accept the half-true premise that the dollar-euro exchange rate is sensitive to relative short-term interest rates, the dollar might have “retained the same purchasing power as the euro” by having the ECB lower interest rates to 3% and the Fed to keep ours at 3%. Or the Fed might have kept the funds rate at 5% and the ECB at 4%. Although either option might have stabilized that particular exchange rate, they would not have had the same effect on global economic growth and therefore on the world demand for oil.

If oil had been priced in dollars and the euro had not appreciated against the dollar, then the euro area would not have been as insulated as it was against the rising cost of oil. Because demand is responsive to price (particularly business demand), Europe would have bought less oil than it did. Or, to use the editorial version, if the U.S. still faced $70 oil then we would try to buy more. Either way, the price in dollars would not have remained the same.

The Economist index covers the prices of 25 commodities, excluding oil and gold, with food accounting for 56% of the index. By April 22 it was up 31% for the year and 3.7% for the month, when measured in dollars.

That was mostly because of food. Industrial commodities were up only 1.6% for the year.

If we are going to blame the rising price of oil and food commodities on the dollar, do we need a different theory to explain why industrial commodities have barely risen?

Here’s another anomaly: Measured in British pounds, the commodity index was up about the same as it was in dollars—31.6% for the year and 4% for the month. That can’t be because Britain has a weak currency—the pound buys 8.9% more dollars than it did a year ago. It can’t be because the Bank of England cut interest rates too much, since 3‑month interest rates are 5.86% in Britain, compared with 1.97% in the U.S.

I happen to agree that the Fed (and ECB) have paid too little attention to the impact of exchange rates on prices of internationally traded commodities. And I suspect the Fed has already gone too far with rate cuts and will have to put rates back up shortly after the election. But to single-out a few sensitive commodity prices that have risen the most (in dollars or pounds) and blame just those prices on the Fed is going too far.