AFGHANISTAN'S NEW government got off to a rocky start last week when police blocked streets leading to their own headquarters in Kabul to protest the naming of a new minister of the interior.

Others cruised the city in trucks, showing off the sort of heavy weapons that aren't normally associated with police work. The point having been made, the protesters dispersed after a few hours, but it was an early shot across the bow of President Hamid Karzai's ship of state.

Fragile hardly begins to describe the situation in Afghanistan. The grand council, or loya jirga, extended its session by three days and in the end approved Mr. Karzai and his Cabinet, but none of the delegates was exactly overjoyed by the results. The Cabinet represents a delicate -- or perhaps intricate -- balancing of ethnic interests, in a country where ethnic hostility was cemented during the Taliban regime and its downfall. If the Cabinet holds together, it will look in retrospect like a political masterstroke. If it doesn't, no one will be surprised.

Prominent at the loya jirga were most of the country's warlords -- men who muscled their way to power as the old Afghan political culture disintegrated over the past 20 years. Some indeed had been heroes when Afghan mujahedeen fought the Soviets in the 1980s, and some were prominent in the fight against the Taliban. But they're a dangerous and murderous group of glorified gang leaders and they still hold most of the sway out in the provinces.

Mr. Karzai chose not to take them on directly. He offered vice presidencies to some, on the theory that it was better to try to keep them inside his tent, and perhaps away from their regional power bases. The move was bitterly criticized by more than a few of the delegates, who thought it would backfire. In the end, two warlords took him up on the offer. Others, including Ismail Khan of Herat and the treacherous Rashid Dostum of Mazar-e Sharif, declined. General Dostum later accepted a vaguely defined post of deputy president.

Mr. Karzai's task now is to extend the influence of his government at the expense of regional leaders without provoking anyone into taking up arms against him. He must satisfy the Pashtuns' sense of entitlement stemming from the size of their community and their traditional leading role; he must also satisfy the Tajiks' rather understandable desire to capitalize on their triumphs over the Taliban last fall. He has to keep Uzbeks and Hazaras and smaller groups from feeling ignored.

And he must accomplish this while at the same time demonstrating to all Afghans that political give-and-take is better than warfare -- a simple but elusive concept. Mr. Karzai does have the support of the United States and its allies on his side, which is considerable. But the real challenge is only now beginning.