The Brzezinski view seems strikingly similar to the perspective of another surprising source, the Pakistani intelligence agency. America has long been suspicious of the Inter-Services Intelligence directorate, which has been infiltrated by Islamic fundamentalists. Now, the Obama administration believes that after the Taliban’s march toward Islamabad, there may be a genuine awakening on the terrorism threat in the I.S.I., which had previously been focused almost exclusively on countering India.

Last week, in a fascinating interview, both for the unusual access and the substance, with the Washington Post columnist David Ignatius, the top Pakistani intelligence official, Lt. Gen. Ahmed Shuja Pasha, expressed skepticism about a U.S. troop surge. At the same time, he showed deep concern that the United States would pull back from its commitments in the region.

“The I.S.I. leadership thinks the United States can’t afford to lose in Afghanistan, and it worries about a security vacuum there that would endanger Pakistan,” Mr. Ignatius reported. “But at the same time, the I.S.I. fears that a big military surge, like up to the 40,000 additional troops McChrystal wants, could be counterproductive.”

It can be reliably reported that this also reflects the views of Pakistan’s president, Asif Ali Zardari, who wants more emphasis on the economic and political development in the region. The Pakistanis are very encouraged by recent congressional action in approving a measure co-sponsored by Senator John Kerry, Democrat of Massachusetts, and Senator Richard Lugar, Republican of Indiana, providing $7.5 billion of economic aid over the next five years.

Mr. Obama has taken on more than a few tough issues this year, though the Afghanistan decision, for the first time, is producing serious fissures among his top policy makers. Vice President Joseph R. Biden Jr. and leading Democratic lawmakers are deeply skeptical of the request from General McChrystal, commander of the International Security Assistance Force and of U.S. forces in Afghanistan; most, not all, of the military, and Secretary of State Hillary Rodham Clinton and her high-powered Afghanistan-Pakistan special representative, Richard C. Holbrooke, are sympathetic.

A pivotal figure in this debate, Mr. Brzezinski guesses, will be Defense Secretary Robert M. Gates, a Bush holdover, who commands considerable respect in Washington. It isn’t clear where Mr. Obama will come down; it will be a surprise, however, if it isn’t somewhere close to where Mr. Gates is.

While opposing a wide-scale escalation, and deeper U.S. involvement, Mr. Brzezinski says “some troop increases may be necessary maybe to hold Kandahar, maybe to hold the main cities in general. But beyond that, where is this sort of dawn in sight in a period of some darkness? I do not see that yet.”