Syria's fractious opposition finally put aside fierce arguments on Sunday to rally behind a new leader within a new coalition that its Western and Arab backers hope can topple Bashar al-Assad and take over the country.

After days of wrangling in Qatar under constant cajoling by exasperated Arab, U.S. and other officials, representatives of groups including rebel fighters, veteran dissidents and ethnic and religious minorities agreed to join a new assembly that can form a government-in-exile. They then unanimously elected a reformist Damascus cleric, Mouaz al-Khatib, as its president.