If the goal is to restrain carbon dioxide emissions, though, he's ingeniously settled on the most expensive and least effective method. One element in his plan is forcing refiners to increase their use of "renewable and alternative fuels" nearly fivefold over the next decade. What the administration most wants to promote is ethanol, but that option has more than its share of defects.

One is that meeting Bush's target would require using the entire U.S. corn harvest to make ethanol -- pushing up corn prices and making ethanol even less cost-effective than it already is. The president suggests that ethanol can also be made from wood chips, grasses and agricultural wastes. But those sources are not yet economical, and it's anyone's guess if they ever will be.

Raising fuel economy standards on cars and trucks, as Bush recommended Tuesday, is a politically appealing idea because it promises progress without pain. But it's like using a screwdriver to hammer a nail.

Instead of discouraging unnecessary driving, it does just the opposite, by lowering the cost of traveling an extra mile. That, as Randall Lutter and Troy Kravitz note in a paper published by the AEI-Brookings Joint Center for Regulatory Studies, will lead to more crashes and more traffic jams. Not to mention that more driving will offset much of the intended fuel savings.

The simplest and most cost-effective way to cut greenhouse gas emissions from cars is to increase taxes on gasoline -- which would encourage Americans to buy more efficient vehicles and drive less. By boosting fuel economy standards instead, Bush can say he's spared us a hateful tax increase. But his approach would impose large, unseen burdens on all of us.

Bush's plan to reduce our oil dependence is full of such hidden costs. And the benefits? They're even harder to find.