AMMAN, Jordan — As Syria’s civil war raged, a Kuwaiti Islamist, Ghanim al-Mteiri, funneled cash from wealthy donors in the Persian Gulf to Syria’s affiliate of Al Qaeda in hopes that it would overthrow the government and lay the foundations of an Islamic state.

So Mr. Mteiri watched in dismay as another, even more violent jihadist organization, the Islamic State in Iraq and Syria, seized a chunk of Syria, stormed into Iraq and not only declared itself an Islamic state, but also demanded that all Muslims swear allegiance to its leader, Abu Bakr al-Baghdadi.

For the first time since its emergence more than two decades ago, the Qaeda of Osama bin Laden finds itself facing a rival jihadist organization with the resources and influence to threaten its status as the flagship movement of violent extremism. For the moment, Al Qaeda has lost ground, but the question remains: Will this new group, which now calls itself simply the Islamic State, endure?

Those still allied with Al Qaeda think the new group will fall victim to the same tactics that somehow have simultaneously made it an enemy of the West and of Ayman al-Zawahri, the leader of Al Qaeda.