U.S. President Donald Trump, left, is greeted by NATO Secretary General Jens Stoltenberg before a summit of heads of state and government at NATO headquarters in Brussels on Wednesday, July 11, 2018. NATO leaders gather in Brussels for a two-day summit to discuss Russia, Iraq and their mission in Afghanistan. (AP Photo/Francois Mori)
U.S. President Donald Trump, left, is greeted by NATO Secretary General Jens Stoltenberg before a summit of heads of state and government at NATO headquarters in Brussels on Wednesday, July 11, 2018. NATO leaders gather in Brussels for a two-day summit to discuss Russia, Iraq and their mission in Afghanistan. (AP Photo/Francois Mori) Francois Mori AP
U.S. President Donald Trump, left, is greeted by NATO Secretary General Jens Stoltenberg before a summit of heads of state and government at NATO headquarters in Brussels on Wednesday, July 11, 2018. NATO leaders gather in Brussels for a two-day summit to discuss Russia, Iraq and their mission in Afghanistan. (AP Photo/Francois Mori) Francois Mori AP

A look at NATO and what the alliance does, past and present

July 12, 2018 06:10 PM