WASHINGTON — The most dreadful burden of the presidency — the power to send men and women to die for their country — seems to weigh heavily on Barack Obama these days. He went to Dover Air Force Base to salute the coffins of fallen troops. He gave a moving speech at the memorial service for victims of last week's killings at Fort Hood. On Veterans Day, after the traditional wreath-laying at Arlington National Cemetery, he took an unscheduled walk among the rows of marble headstones in Section 60, where the dead from our two ongoing wars are buried.

As he decides whether to escalate the war in Afghanistan, Obama should keep these images in mind. Geopolitical calculation has human consequences. Sending more troops will mean more coffins arriving at Dover, more funerals at Arlington, more stress and hardship for military families. It would be wrong to demand such sacrifice in the absence of military goals that are clear, achievable and worthwhile.

And what goals in Afghanistan remotely satisfy those criteria?

The Washington Post reported Wednesday that the U.S. ambassador in Kabul, Karl Eikenberry, recently sent two classified cables to officials in Washington expressing what the newspaper described as "deep concerns" about sending more troops now.

Gen. Stanley McChrystal, chosen by Obama to lead U.S. forces in Afghanistan, has asked for perhaps 40,000 additional troops to carry out a counterinsurgency campaign. Armchair Napoleons in Washington, comfortably ensconced in their book-lined offices, insist that Obama must "listen to the generals." But Eikenberry was a four-star general until Obama named him ambassador earlier this year. He commanded U.S. troops in Afghanistan in 2006-07. He needs to be heard, as well.

In what were described as sharply worded cables, Eikenberry reportedly expressed serious doubts about the willingness of Afghan President Hamid Karzai to tackle the corruption and mismanagement that have made his government so unpopular and ineffectual — and that have allowed the Taliban to effectively regain control of much of the country.

Karzai, you will recall, committed what observers described as widespread, blatant election fraud in "winning" a new term in office. In many parts of Afghanistan, the Karzai government is seen as so weak and corrupt that the Taliban has been able to move in as a lesser-of-two-evils alternative.

It is axiomatic that a successful counterinsurgency program requires a partnership with a reliable, legitimate government. If the Karzai regime is not such a partner, the goal that McChrystal would be pursuing with those extra 40,000 troops is not achievable.