Two months after Soviet troops withdrew from Afghanistan under pressure from U.S.-backed guerrillas, critics say America no longer has a coherent and effective policy for promoting the rebel cause.

The resistance is beset with difficulties, both military and political, and the Soviet-backed government in Kabul is putting up a more effective fight for survival than was expected.Congressional critics and private analysts say Washington is doing little more than standing idly by.

"It seems to me our policy is watching and waiting and hoping for the best. Surely we can exert more influence than we are," said Gordon Humphrey, a Republican senator who is one of the most ardent resistance-supporters in Congress, at a recent Senate hearing.

Others say Washington is providing the wrong weapons and failing to press the rebels to form a representative government - partly because Afghanistan is no longer a priority.

"What's the aim?" asked Robert Neumann, former U.S. envoy to Kabul. "It was to get the Russians out. That accomplished, what government Afghanistan has is a lesser objective."

The Kabul government, which Washington says is illegitimate, has clung to power longer than many had predicted it could without Soviet soldiers to prop it up. The last Soviet troops left on February 15.

Resistance forces ringing the strategic city of Jalalabad have found it difficult to adjust from guerrilla fighting to conventional siege tactics. Hampered by poor coordination between rival factions, plagued by bombings and minefields, they have been bogged down for six weeks.

Some Western diplomats say the rebels cannot win a military victory and a negotiated settlement may be required.

The State Department rejects that view, believing the fall of the Kabul government is inevitable. But independent Afghanistan-watchers feel the administration of President Bush is not doing enough to help the rebels win.

Afghanistan specialist Marin Strmecki of the private Center for Strategic and International Studies, who has just returned from a month with the rebels besieging Jalalabad, says the United States is still providing them with guerrilla-war weapons when they need conventional armaments.

"The administration has failed to make a transition in the kinds of weapons needed . . . heavier artillery, better longer-range anti-tank weapons, more Stingers (shoulder-fired anti-aircraft weapons) . . . and a higher altitude, longer-range anti-aircraft weapon," he said in an interview.

The anti-aircraft weapons are needed because resistance units around Jalalabad are being pounded by elusive and deadly MiG-27 warplanes, he said.

A State Department Afghanistan watcher said he knew of no plans for increasing the number or sophistication of U.S. weapons. He insisted Washington was giving the rebels what was needed.

Strmecki said that if the resistance failed to build a broad-based government, the country would break into fragments under rival chieftains. Moscow could then exert leverage over some warlords.

Washington so far has refused to extend diplomatic recognition to the interim government because it has failed to establish sufficient control. Bush has decided to appoint a special envoy to the rebels, diplomat Peter Tomsen.

The rebels have also failed to allay fears of looting and massacres in government-held cities, Afghan specialists say.

Sen. Humphrey has urged Washington to take direct control of which groups get the arms, wresting that responsibility from Pakistan's military, which now routes the arms.