Some have argued over the last decade that the best and most cost-effective way to prevent terrorism in the U.S. is through good intelligence work rather than through lengthy wars in Muslim countries. The latest example supporting this line of thinking occurred today when it was revealed that an Iranian-backed plot to assassinate the Saudi ambassador to the United States was disrupted by the FBI and the Drug Enforcement Agency.

An Iranian American, Manssor Arbabsiar, 56, has been arrested in the case. Gholam Shakuri, an Iran-based member of the secret Quds Force unit of Iranian’s Revolutionary Guard, was also charged but is not in custody.

The two men were charged with conspiracy to murder a foreign official, conspiracy to use weapons of mass destruction, and conspiracy to commit an act of terrorism, among other counts. Arbabsiar has confessed to the charges and is cooperating with authorities in custody according to government officials. The men planned to detonate a bomb at a busy Washington restaurant, killing Adel Al-Jubeir, the Saudi Arabian ambassador to the U.S., and scores of innocent bystanders.

However, a DEA informant posing as a member of Los Zetas, a Mexican drug cartel, infiltrated the plot. The Zetas cartel was to be paid $1.5 million to carry out the attack, and two advance payments of nearly $50,000 each were wired to an FBI-controlled bank account in August.

Los Zetas, founded by a group of Mexican Army Special Forces deserters, began as the military wing and private mercenary army of the Gulf Cartel. Los Zetas took their name from the radio code used for top-level officers in the Mexican army. After the arrest of the Gulf Cartel’s leader, Osiel, Cárdenas Guillen, the Zetas began operating independently, which led to the bloody turf war that has engulfed Mexico. The DEA describes them as perhaps “the most technologically advanced, sophisticated and violent of the paramilitary enforcement groups.”

The DEA informant who helped crack the case, had been charged with a drug offense and agreed to cooperate in the investigation by posing as a member of the Zeta drug cartel in a meeting with the conspirators in May. Later meetings took place in the U.S. and Mexico.

FBI Director Robert Mueller told reporters today that the case “reads like the pages of a Hollywood script.” But I believe it reads more like a recipe for winning the war on terror.