Less than a month after hosting US President Donald Trump and 50 Muslim leaders, the Kingdom of Saudi Arabia's alliance of Sunni states is in tatters, squandered on a vendetta. The Saudis' self-inflicted damage comes as tensions with its arch nemesis Iran are becoming more dangerous than ever. Support in the United States for the kingdom is polarizing.

King Salman bin Abdul-Aziz Al Saud demonstrated the impressive convening power of the Saudi government last month by hosting the American leader and those of dozens of Muslim countries. With a few exceptions (Algeria, Oman), most Islamic heads of government came to Riyadh for the summit. The Saudis rightly announced that the summit was a strong display of unity against terrorism and Iran, one that probably no other country in the Islamic world could have arranged. Saudi wealth and the king's status as the custodian of the Two Holy Mosques account for the success.

The longstanding rivalry between Saudi Arabia and Qatar, the world's only two Wahhabi states, is now shattering the unity built just last month. Qatar has long been an irritant and gadfly of the Saudi royal family and other leaders. While suppressing dissent at home, Qatar has encouraged it abroad. It shares an enormous natural gas deposit with Iran and together with Oman has been a voice in the Gulf Cooperation Council (GCC) for keeping ties open with Tehran. Saudi Arabia is apparently determined to put Qatar in its place.

Now the GCC is broken into three camps. There is the Saudi-Bahrain-UAE bloc, which has severed ties and closed borders to Doha. Then come outliers Kuwait and Oman, leaving Qatar alone. Although close to Riyadh, Kuwait is trying to mediate what has become the worst split in the history of the GCC.