Why would five Iranian speedboats bluff an attack on a U.S. Navy squadron?

Start with a big fact: Under the mullah-led thieves' regime, Iran has become an explosive political mix of ethnic, economic and ideological fragments, a mosaic powder keg.

The Ayatollah Khomeini's 1979 Islamic Revolution failed, then fossilized, leaving a corrupt junta of robed kleptocrats who use the dictator's classic tools of murder, terror and economic favoritism to control an impoverished, splintered and increasingly restless populace.

Moreover, factions within the mullahs' hierarchy spar with one another. Throwing a risky punch at the United States or Great Britain serves two distinct purposes. Armed bravado directed at "the Great Satan" and British imperialists appeals to Iranian nationalists -- at least, it has in the past. Khomeinist radicals, like Iranian president Mahmoud Amadinejad, contend that confrontation with the United States also strengthens them.

The reasoning may appear convoluted, wickedly Byzantine, but if Iran's domestic malaise continues to get worse, and domestic tensions seed violent street demonstrations, the most radical Khomeinists apparently believe dramatic attacks on U.S. forces -- such as the destruction of a U.S. Navy capital warship -- enhance their political position. Their willingness to run great risks demonstrates they are "the true believers." An extended confrontation with the United States also gives them the opportunity to portray their domestic opponents as traitors -- and then kill them.

This week's round of Iranian "gunboat diplomacy" by five armed Revolutionary Guards' speedboats fulfills both political purposes, and comes as U.S. President George Bush prepares to visit the Middle East. The incident echoes the March 2007 kidnapping of British sailors and marines who were patrolling Iraqi waters in small, inflatable boats.

Both incidents fit into a consistent historical pattern, one the American Enterprise Institute's Michael Ledeen believes the U.S. government ignores at its own long-term peril. "It is never surprising when the Iranians attack us," Ledeen told me the day after the gunboats' display of moxie, "because they have been attacking us for 30 years."

The best long-term U.S. strategy is political and economic -- encouraging an active domestic political opposition to Iran's clever religious leaders while whittling away at the clerics' graft-crammed Swiss bank accounts. This incremental strategy, however, takes time and perseverance.

Could Revolutionary Guard speedboats sink an American warship? A suicidal zealot in an explosive-packed Boghammer could zig-zag his way through U.S. defenses, particularly if his boat was one of several in a "swarm." Drop the analytic resolution from the "macro" strategic political view to the "micro" tactical military aspects of the incident, and the Revolutionary Guards' naval action has all of the elements of a "close-in probe" designed to test U.S. Navy reactions. However, an American cruiser, destroyer and frigate deployed in a flotilla are a very dangerous target -- nothing remotely comparable to vulnerable British sailors in a rubber raft.

The deadly suicide boat attack on the destroyer USS Cole in October 2000, as it lay anchored in the port of Aden, Yemen, made "close in" defense of U.S. warships a priority. The U.S. Navy began arming its capital ships with .50 caliber heavy machineguns, assorted light machineguns and 25 millimeter automatic cannons (like those mounted on U.S. Army Bradley armored infantry vehicles). Crewmen also occasionally deploy shoulder-fired Stinger anti-aircraft missiles (another infantry weapon) as an additional defense against light, low-flying airplanes (a Cessna on a suicide mission) or drone aircraft carrying explosives

In June 2005, I spent three days on the cruiser USS Normandy, deployed near Iraq's Al Basrah offshore oil terminal. The Normandy carries long-range missiles, a modern naval cannon and electronics capable of identifying targets hundreds of miles away. However, Iranian dhows operating beyond the terminal's exclusion zone were the most immediate threat, and the huge capital ship bristled with light automatic weapons manned by sailors. After inspecting a 50 caliber mount, I jokingly called the Normandy the "world's biggest PT boat." World War II-era U.S. PT boats often fought Japanese barges and small craft up close, infantry-like combat waged in shallow seas.

Naval mines are the real threat to big ships operating in the Persian Gulf. A naval mine can break and sink a ship. But mines are material things, deadly lumps without personality or religion. Sinking an American destroyer with a mine lacks the brazen testosterone, theological resolve and sensational media impact of a jihadist-manned speedboat braving the hail of fire to slam into the arrogant infidel warship's disintegrating armor.