As its losses mount in Iraq, will a less potent Islamic State merge with its precursor, al-Qaida?
That speculation ramped up this week after Iraqi Vice President Ayad Allawi told Reuters he had information from Iraqi and regional contacts that "the discussion has started now" concerning a "possible alliance" between the two militant groups.
Referring to IS leader Abu Bakr al-Baghdadi and Ayman al-Zawahiri, the head of al-Qaida, Allawi said, "There are discussions and dialogue between messengers representing Baghdadi and representing Zawahiri."
But analysts say ideological and tactical differences and years of open animosity between leaders will need to be overcome before the groups can align.
"While dialogue is one thing, a prospective alliance is quite another," Milo Comerford, an analyst at the Centre on Religion and Geopolitics in London, wrote this week in Newsweek magazine.
'Little love lost'
"There has been little love lost between the two jihadi groups," he wrote. "A recent IS magazine described al-Qaida as 'Jews of jihad,' while Ayman al-Zawahiri has openly condemned Abu Bakr al-Baghdadi since 2015, accusing IS's leader of having an adverse effect on the jihadi cause and creating fitna [discord]."
IS was founded as an offshoot of al-Qaida in Iraq in 2004, in a movement spearheaded by Jordanian jihadist Abu Musab al-Zarqawi. As IS started gaining more influence in Iraq and Syria in 2014, it split from al-Qaida, and the two groups have since engaged in acrimonious and sometimes bloody competition over the leadership of the jihadist cause.
For years, IS has been siphoning off followers of al-Qaida.
"IS is pressuring al-Qaida's affiliates to defect," Barak Mendelsohn, an associate professor of political science at Haverford College in Haverford, Pennsylvania, said at a Brookings Institution forum in January. "While it has failed so far to shift their allegiance, it has deepened cracks within the branches and persuaded small groups of al-Qaida members to change sides."
Still, there are fundamental religious differences between the two, analysts say.
"Zawahiri has criticized the very existence of IS by claiming that the selection process by which Baghdadi became caliph was not according to the Prophetic tradition," Comerford wrote. "Across a series of statements, Zawahiri has worked to undermine the religious foundation on which IS depends for its appeal within the jihadi community."
Territorial, political issues
While both groups share an extreme anti-Western Sunni jihadi ideology, there are political differences that are rooted in territorial and political structure.
IS is in favor of establishing a government with a head figure who it officially names a "caliph." It is willing to annihilate any local group that refuses to pledge allegiance to the caliphate — its self-styled Islamic State.
Although the goal of al-Qaida also is to establish a caliphate, its leaders prefer to focus on targeting the United States and the West, which they see as the primary enemies of Islam, analysts say.
"It is very hard for them to bridge that difference," said Middle East expert David Pollock, an analyst at the Washington Institute for Near East Policy.
While desperation may force al-Qaida and IS to explore coordination options, Pollack said, "I think the different personalities, the different ideologies, and in fact, the survival instinct of each group works against that."
And it's unlikely IS would diminish its goals to join with al-Qaida, analysts say.
"IS could settle for consolidating its caliphate in the territories it currently controls, but its hubris and messianic zeal do not allow for such limited goals," analyst Mendelsohn said. "It is committed to pursuing military expansion alongside its state-building project. This rigid commitment to two incompatible objectives is perhaps the Islamic State's biggest weakness."
As for combining forces in other countries — including Syria, Yemen, Iraq, Afghanistan and Somalia — analysts say specific conditions, and in some cases open hostilities between al-Qaida and IS, make creating alliances highly unlikely.
In Iraq, retreating IS followers could find small havens in al-Qaida, at least temporarily, officials say.
"It is true that al-Qaida was born in Iraq and it seems like such an alliance will make the two groups stronger if they combine at least locally," Kurdistan Regional Government spokesman Safeen Dizayee told VOA. "But al-Qaida is never able to achieve what IS achieved in Iraq in 2014. Their sun is setting here."
And if both groups settle in one Iraqi locale, it's likely the U.S-led coalition in Iraq will target them, experts say.
"If they combine, that may have the unintended effect from their standpoint of encouraging the United States, the coalition, and our local partners in these predominantly Muslim countries and societies … to fight against them as one," analyst Pollack told VOA.