“Give me a one-handed economist,” President Harry S Truman once lamented. “All my economists say, ‘On the one hand,’ then, ‘But on the other …’”

That's pretty much the case on Capitol Hill these days as congressional committees continue to expend time and resources on what seem like permanent hearings into whether speculators, hedge funds, and pension funds are factors in the steep run-up in oil and ag commodity prices.

The parade of high-powered industry and organization execs offering testimony has pretty much offered variations on the same two themes: (1) No, it's just supply/demand at work and the market should be left alone to do its thing, and (2) the staggering sums of speculative money (as much as $5 trillion per day) have artificially inflated prices, with the public getting shafted with higher costs for everything from avocados to toilet tissue.

“All the data modeling and analysis we have done to date indicate there is little economic evidence to demonstrate that prices are being systematically driven by speculators in these markets,” said Jeffrey Harris, chief economist, and John Fenton, director of market surveillance, both with the Commodity Futures Trading Commission, in their prepared statement.

“Simply put, the economic data show that overall commodity price levels, including agriculture commodity and energy futures prices, are being driven by powerful fundamental economic forces and the laws of supply and demand.”

Proposals before Congress to limit or further regulate speculative activity could “severely compromise the ability of commodity futures markets to accommodate the needs of commercial firms to hedge price risks,” said Scott Irwin, professor of agricultural and consumer economics at the University of Illinois at Urbana-Champaign.

“A number of witnesses have testified that Congress could reduce the price of energy by 50 percent within 30 days just by cracking down on futures markets,” said Daniel J. Roth, president/CEO of the National Futures Association. “I have not heard even a shred of data or empirical information to support that claim.”

Congress, he said, is “being asked to roll the dice with the American economy.”

On the other hand … “The excessive speculation in commodity markets is having a devastating effect,” said Rep. Bart Stupak, D-Mich. He said speculators now control 71 percent of the oil on the market.

Speculators “have always been integral to market function,” said Bob Stallman, president of the American Farm Bureau Federation, “but they are now playing an exponentially greater role than ever before.”

He cited statistics that total index fund investment in corn, soybeans, wheat, cattle, and hogs has increased to $42 billion and noted that independent analyst Steve Briese “calculated that at the end of March index funds had effectively bought 36.6 percent of the 2007 domestic soybean crop and 62.3 percent of the domestic wheat crop.”

He called for “additional transparency” for the funds “so the markets can fulfill their primary functions of price discovery and risk management.”