What kind of a U.S. ally regularly embarrasses his supporters with threats and complaints?

An essential one, it appears. Top U.S. leaders took special pains this week to forgive Afghan President Hamid Karzai’s threat to join the Taliban. Secretary of State Hillary Rodham Clinton called Karzai’s remarks unfortunate, but understandable because he is under such pressure.

Karzai’s disconcerting actions included overtures to Iran’s president Ahmadinejad, but Secretary of Defense Robert Gates took this in stride. “This is a man who’s, first of all, a political leader,” he said Sunday. “He has domestic audiences as well as foreign audiences.”

It is possible to believe that Karzai is showing political leadership in rallying support among his countrymen for a strong central government. He has traveled far from the safety of Kabul in this effort, and was targeted by rockets during a recent visit to a northern province. At that time, he called on insurgents to help him free Afghanistan from westerners, saying, “As long as you fight, (the foreigners) won’t leave.”

The image of a strong, nationalistic leader is contradicted by many critics who point out that Karzai was elected in a fraudulent election and leads a corrupt and ineffective government. The country is ruled by warlords, and the opium trade continues unabated. To many, it is unlikely that Karzai can muster the leadership needed to unite his country.

But President Obama’s recent visit to Kabul, and the words of support from Clinton and Gates show that the administration has concluded that Karzai’s leadership is essential to ending the U.S. campaign in Afghanistan. As the last Afghan election showed, there is no other credible candidate for the U.S. to support.

Under the leadership of Gen. Stanley MChrystal, U.S. and NATO troops are preparing for a major summer offensive in Kandahar.  The goal is to defeat the insurgents while winning support in the countryside, setting the stage for a strong central government able to keep the Taliban from returning to power.

U.S. and NATO leaders have made a practical and well-founded judgment that Afghanistan’s tribal leaders and dealmakers are essential to reaching this goal. Strengthening the hand of Hamid Karzai may not be a step toward real democracy, but it may be the best strategy for stabilizing a poor and divided country.