Crude oil prices hit $120 a barrel this month, translating into gas pump prices above $4 a gallon in parts of the United States. As a result, the rallying cry of energy self-sufficiency is gaining strength, reinforcing the U.S. policy of promoting renewable fuels, particularly corn-based ethanol, to reduce dependence on imported oil.

But a different rallying cry—food self-sufficiency—is becoming louder in many developing countries where rice, wheat and other staples are in such short supply that food riots have erupted. China, India, Argentina and several other countries have raised export restrictions on key crops to ensure food supplies for their consumers. That move has further increased world prices.

It is important to remember two key lessons from similar chaos in world food markets in 1973-74. First, attempts to gain domestic price stability create global price instability. And second, once policies are established to protect food markets, they are not easily dismantled. It took two decades for rice trade to expand in Asia, and even then, it remained limited.

The United States must take a lead in confronting the world food crisis. But to do so will require a genuine commitment to improving the well-being of people around the world—and recognizing that energy self-sufficiency at home can mean widespread starvation abroad.

In its starkest form, the global food crisis is about rising agricultural commodity prices that place hundreds of millions of poor people at greater risk of malnutrition. Most of the 800 million people globally who survive on a dollar a day or less live in rural areas and work on farms.

The two- to fourfold jump in prices during the past 18 months for internationally traded commodities, such as rice, wheat, corn, soy and vegetable oils, has resulted in fewer and smaller meals for the poor. The rise in the number of malnourished people globally is only beginning to be tallied.

High food prices have been associated with high petroleum prices. The cost of crop production is up, the value of the dollar is down, and biofuels are an attractive alternative to fossil fuels for transportation. Diverting one-fifth of the U.S. corn crop to corn-ethanol production and setting a renewable fuels mandate of 20 percent of U.S. motor fuel consumption by 2022— a fourfold increase in 15 years—has driven up prices for corn and substitute crops, especially soybeans.

Demand for corn, soy and other livestock feeds already had been rising due to increased meat consumption by China and other emerging economies. Add some major weather, pest and disease shocks, and the market for staple agricultural commodities tightened dramatically in 2006 and 2007.

Moreover, a surge in speculative activity has exacerbated market volatility.

How should the three presidential candidates, in particular, address this crisis?

For starters, the United States should retreat from its heavy promotion of corn-based ethanol and allow the markets to settle. Although the 2008 U.S. Farm Bill, passed by the House and Senate last week, includes a reduction in the ethanol blending credit from 51 cents to 45 cents per gallon, the subsidy remains high and is offset by other biofuels production incentives.

President Bush plans to veto the bill, but both the House and the Senate passed it with more than the two-thirds majority needed to overturn a veto. The presidential candidates, Sens. John McCain, Barack Obama and Hillary Rodham Clinton, were all absent for the vote.

The bill increases the Food Stamp Program by $10 billion to help poor Americans buy food at higher prices, but there are no measures that will assure developing countries and international markets that global food supplies will be adequate and that prices will come down. Congress needs to endorse the World Food Program's new strategy of providing food aid in the form of cash instead of surplus grain shipments, a strategy that would allow food-deficit countries to purchase their calories regionally and thereby promote agriculture closer to home.

It also would be wise for the U.S. Agency for International Development to expand, not abolish, investments in agricultural research for low-income countries.

The world can produce plenty of crops at reasonable prices for food and feed, if appropriate agricultural investments are made. But it cannot produce enough crops for food, feed and fuel at prices affordable to half of the world's population.