"It was a sobering reminder of the extraordinary sacrifices that our young men and women in uniform are engaging in every single day, not only our troops but their families as well," Obama said from the White House, reflecting briefly on his surprise middle-of-the-night trip to Dover Air Force Base to observe the return of the fallen Americans to the United States.

Speaking softly and somewhat haltingly, Obama said losses such as these were "something that I think about each and every day."

Asked whether the somber experience - watching cases carrying the remains come off a giant C-17 cargo plane one by one in the darkness and meeting privately with families so fresh in their grief - will affect his overhaul of the U.S. strategy in Afghanistan, the president did not hesitate to say that it would.

"The burden that both our troops and their families bear in any wartime situation is going to bear on how I see these conflicts," he said.

By many accounts, it was a difficult night. After a 40-minute helicopter ride around midnight to the Delaware base where U.S. forces killed overseas come home, Obama went immediately to a chapel to speak with relatives of the fallen. Their loved ones had died just two or three days before. The families did not know of the president's visit until they arrived at the base.

Of the 18 Americans on the C-17, 10 - including three Drug Enforcement Administration agents - were killed Monday when a military helicopter crashed returning from a firefight with suspected Taliban drug traffickers. The eight others were killed Tuesday by roadside bombs.

The military calls the process of removing remains from the plane a dignified transfer, not a ceremony, because there is nothing to celebrate. Dignitaries, in this case including Obama, board the plane for prayers, then stand in a line of honor outside as soldiers carry each case into a waiting van.

Most of what Obama saw was private. An 18-year ban on coverage of Dover homecomings dating to the 1991 Gulf War was relaxed this year under Obama's watch. Now, families can decide whether cameras can document the return. Yesterday, the return of only one of the 18 was open to the media. His name was Dale R. Griffin, an Army sergeant from Terre Haute, Ind.

His remains were the last to be carried past the president. It was not quite 4 a.m. By 4:45, five hours after leaving the White House, Obama was back on the South Lawn. He walked inside, alone.

White House press secretary Robert Gibbs said later that Obama remained quiet on the way back, saying thanks to his team but little else. "I don't think you can go out there and not understand what you are seeing," said Gibbs, clearly shaken by the experience. "It's hard not to be overwhelmed."

The president's trip comes at a pivotal moment for the Afghanistan war. October has become the deadliest for U.S. forces in Afghanistan since the war began eight years ago, with at least 55 troops killed.

Obama is weighing strategies to overhaul the war so that al-Qaeda cannot take root again in Afghanistan and more U.S. lives and money aren't sunk into an effort that doesn't work. Obama holds his next war-council meeting with top staff today, but aides say he is still weeks away from a decision.