On Monday, President Obama restated his support for Mexican President Felipe Calderón's aggressive tactics in the fight against drug trafficking. He also reiterated his support for a drug security plan with Mexico that is similar to the failed drug plans of past administrations.

Before Washington ramps up yet another losing war on drugs, it should take a clear-eyed look at how its current strategies are affecting the supply and demand of drugs. Congressman Eliot Engel (D) of New York has introduced a bill to do just that.

Washington would be wise to back Congressman Engel's initiative because there has not been a thorough, frank evaluation of the fight against drugs in decades. The drug czar office's annual report is not enough. Recommendations by an independent commission, however, could generate the consensus and strategy we sorely need.

The cornerstone of US drug policy at home and abroad is to reduce the drug supply (from crop eradication to border seizures) in order to increase the domestic price of drugs. The idea is to deter both potential consumers and producers from entering the drug market.

It hasn't.

Since May 1971, when President Richard Nixon proclaimed a "war on drugs," Washington and the Western Hemisphere have been unable to win it. Every claimed victory has turned out to be, in the end, a fiasco.

Consider Mexico and Jamaica in the 1970s and early '80s. Mexico cracked down on marijuana production. But that simply shifted production to Colombia and then to the US, while allowing heroin production and cocaine trafficking to rise. Jamaica's effort against marijuana similarly backfired and today, drug-related violence is at a high.

Colombia has been the most high-profile, high-stakes test case of the hemisphere's struggle against drugs.

A decade ago, the Clinton administration launched the multiyear, billion-dollar Plan Colombia.

The Bush administration then expanded Plan Colombia and provided even more funding.

With those funds, Bogotá has spent the past 10 years eradicating illicit crops over an area that is 2-1/2 times the size of the state of Delaware. It has extradited more than 600 Colombian nationals to the United States. It has dismantled the large, brutal, Medellín and Cali cartels; has criminalized all the phases of this illicit business; and has launched an attack on both guerrillas and paramilitary-linked drug emporiums.

And yet, after all that, production of cocaine in Colombia actually increased, and the drug network remains intact.

So why is the Obama administration extending a similar plan – the Mérida Initiative – for Mexico?

Plan Colombia didn't work for a number of reasons. It was based on a lopsided policy of shared responsibility that did not work in this case. The emphasis was on supply control and not on demand reduction. What good does cutting back on coca leaf production do if there are still people addicted and willing to pay high sums for cocaine? It relied too heavily on short-term benchmarks instead of long term implications. Then there were the negative effects on human rights, civil-military relations, the environment, and the rule of law – all very fragile in Latin America.

If Mr. Obama intends to avoid a potentially catastrophic scenario in a bordering country, then he should support Engel's initiative. The establishment of a Western Hemisphere Commission could be a rather inexpensive, short study. The commission would be required to submit recommendations on future US drug policy to Congress, the secretary of State, and the director of the Office of National Drug Control Policy 12 months after its first meeting.

Gathering the reports and analysis and putting the minds together of leading experts from the Americas, nongovernmental organizations, policymakers, and the media would produce a more nuanced understanding of the situation. It is only by analyzing our current and past problems that we can make true progress now.

Rafael Pardo is a former Colombian senator and defense minister. He is the current Liberal party nominee for president in the 2010 election. Juan Gabriel Tokatlian is a professor of international relations at the Universidad Di Tella in Argentina.