“The key here is an Afghan surge, not an American surge,” Senator Carl Levin, a Michigan Democrat who heads the Armed Services Committee, said on CBS’s “Face the Nation.” “And if the president lays out the case for why our combat forces that are going particularly to the south will increase the speed-up of the Afghan Army, it seems to me that that would be very, very important.”

With the cost of the war rising, some Democrats have even talked of a surtax. And a Republican senator, Richard G. Lugar of Indiana, asked: “If we were talking about several years of time, how many more years beyond that? What is the capacity of our country to finance this particular type of situation as opposed to other ways of fighting Al Qaeda and the war against terror?”

At West Point, Mr. Obama was expected to describe commitments from Afghanistan’s president, Hamid Karzai, and specific benchmarks his government must meet: to crack down on corruption, deploy well-trained Afghan troops and police officers, and focus on development in one of the world’s poorest nations. Mr. Obama was expected to be far less specific about Pakistan, where Taliban leaders are commanding operations across the border against American forces, and where Al Qaeda’s central leadership still lives.

“We agree that no matter how many troops you send, if the safe haven in Pakistan isn’t cracked, the whole mission is compromised,” said one official who has participated in the debate over the strategy. “But if you make too many demands on the Pakistanis in public, it can backfire.”

The problems in Afghanistan have only been compounded by the fragility of Mr. Obama’s partner in Pakistan, President Asif Ali Zardari, who is so weak that his government seems near collapse. On Friday, Mr. Zardari relinquished his position in Pakistan’s nuclear command structure, turning it over to the prime minister, in what appeared to be an effort to avoid impeachment or prosecution, and retain at least a figurehead post.

On Sunday, one of the Obama administration’s staunchest allies, Prime Minister Gordon Brown of Britain, joined in the campaign to press Pakistan to step up attacks on Al Qaeda’s leadership in Pakistan’s unruly tribal areas and other militant groups there. “People are going to ask why, eight years after 2001, Osama bin Laden has never been near to being caught,” Mr. Brown told Sky News, “and what can the Pakistan authorities do that is far more effective.”

White House officials have said relatively little about the Pakistan side of the administration’s evolving war strategy, in part because they have so few options and so little leverage. They cannot send troops into Pakistan, and they cannot talk publicly about one of their most effective measures, the Central Intelligence Agency’s Predator drone strikes in the country.