Judy Woodruff:

But first: Over the past several years, the United States military increased its presence and broadened its mission in Africa.

One place where that expansion is best seen is Niger in West Africa, part of what's known as the Sahel region. The U.S. Air Force has built a huge new base there, from which it launches drone aircraft.

But as in other hot spots where drones fly, in Niger, those operations are controversial.

Special correspondent Mike Cerre was granted rare access to the base.