Obama On War Decision: 'You Feel It Viscerally'

President Barack Obama spoke in personal terms Wednesday about the weight of war, calling his middle-of-the-night trip to Dover, Del., to greet the remains of fallen soldiers the most powerful moment of his presidency.

Obama said his decision to send 30,000 more troops into the Afghanistan war was not just an analytical decision about the best strategy.

Obama in late October made a surprise midnight flight to Dover Air Force Base to greet the flag-draped cases of 18 Americans killed in Afghanistan. He took part in a solemn process that involved transferring the fallen from a C-17 plane to a transport vehicle after meeting with family members of those killed.

"Walking up the ramp of the transport plane by myself and seeing those caskets — it's indescribable," Obama said. "It reminds you of the extraordinary courage and sacrifice that these young men and women are willing to make. But it also reminds you that you have the solemn obligation to make the best possible decision."

The president said he had foreseen the difficulty and weight of sending young men and women into war.

Yet he said, "When you're in the midst of making the decisions, though, nothing compares. And when you meet with the families and you talk to soldiers who've come home disabled as a consequence of their service — the sheer emotional force of that, I think, is something you can't anticipate. It's something that hits you like a ton of bricks."

Obama spoke on Wednesday with ABC News' Charlie Gibson, the departing anchor of "World News Tonight."