PBS News Hour S42 E158 August 9, 2017

Wednesday on the NewsHour, President Trump's comments on North Korea raise alarms in Asia and elsewhere, and prompt a threat on Guam from Pyongyang. Also: Steps the U.S. is taking to upgrade its own nuclear arsenal, how livestock breed antibiotic-resistant superbugs, a woman who brings health care to others in Somaliland and a new book from a woman who dared to drive in Saudi Arabia.