He allowed American forces to deploy to Yemen and conduct drone strikes on suspected al-Qaida militants, which also killed civilians.
As the Houthis and their allies marched south and then threatened to capture the port city of Aden, Saudi Arabia announced in March 2015 it would lead a coalition of Arab nations to join the conflict.
A United Nations report said coalition airstrikes were responsible for 60 percent of civilian deaths over a yearlong span starting in July 2015.
Yemen's then-President Ali Abdullah Saleh waves to his supporters during a rally in Sanaa, Yemen, April 15, 2011.
The Saudi-led war shows the neoconservative policies of Saudi Crown Prince Mohammed bin Salman, the son of King Salman and the architect of the coalition intervention in Yemen, and Abu Dhabi's powerful Crown Prince Mohammed bin Zayed Al Nahyan.