...The weak dollar is pummeling equities, disrupting the economy, distorting global trade and giving hundreds of billions of dollars in windfall revenues--through skyrocketing commodity prices--to our adversaries such as Iran and Venezuela. Not since Jimmy Carter has the U.S. had a President so oblivious to the damage done by an increasingly feeble greenback. ...The U.S. Treasury Department could buy dollars in the currency exchange markets. Our allies would gladly cooperate with such an operation; their exports are being hurt more and more. The Fed could mop up some of the excess liquidity it has created since 2004, even as it...