Yemen's rebel alliance is steadily weakening. Recently, former Yemeni President Ali Abdullah Saleh, who is leader of the General People's Congress, made public overtures to Saudi Arabia distancing himself from his Houthi allies. Though Saudi Arabia considers Saleh an enemy, it considers him less of a threat than the Houthi rebels, who were a problem for Saudi Arabia far before they struck a loose alignment with Saleh's GPC party in 2015....