In 2015, Saudi Arabia initiated a bombing campaign against Yemen that contributed to what is now the world's largest humanitarian crisis. Today, 14 million people in Yemen face starvation. Journalist Robert Worth says the country is "no longer a functioning state" — and that Americans share some of the blame, since the Obama administration backed the Saudis. "We gave a green light for it in 2015, and then we stood by and let it continue as it got worse and worse," he says.