The early death toll is small compared to the instant impact of earthquakes and tidal waves, but the UN calls flooding in Pakistan the worst natural disaster in modern memory. In a region the size of Italy, the basis of civilization is being washed away: homes, roads, bridges, livestock and crops. Twenty million people face absolute ruin. Refugees are fighting over aid that's been slow in coming, and militant groups are trying to fill gaps left by government ineffectiveness. We look at the humanitarian crisis and the response from inside and outside. Can the US leverage its aid to improve a dismal image?