Study past mistakes before you repeat them.

As Congress contemplates banning speculators from trading oil contracts, it should study its past efforts to rein in speculation:

In 1958, Congress officially banned all futures trading in the fresh onion market. Growers blamed "moneyed interests" at the Chicago Mercantile Exchange for major price movements, which could sink so low that the sack would be worth more than the onions inside, then drive back up during other seasons or even month to month. Championed by a rookie Republican Congressman named Gerald Ford, the Onion Futures Act was the first (and only) time that futures trading in a specific commodity was prohibited, and the law is still on the books.

Even after the nefarious speculator had been banned, the volatility of onion prices remained high. Ironically, growers now want the speculators back.