President Joe Biden has taken steps to ease what the United Nations calls the world’s worst humanitarian crisis — in Yemen. He has halted sales of weapons that are being used in the war there and has reversed an executive order that would have prevented humanitarian aid from reaching most Yemenis. But as Shireen al-Adeimi, a Yemeni American activist, tells host Marco Werman, a resolution to the crisis in Yemen will take more than executive orders.