I see your B.O. and raise you a G.W.
Where is the divided highway, Ialmisry? Is that for a nonMuslim section of town called Jeddah in an extremist country?
The biggest obstacle to unity with R.C. is that they have the Pope being everyone's supreme ruler or something, while a Patriarch would be like his subject. So any
disagreement on doctrine would subject our position to the RC one. It is a practical concern that goes above anything. You can't agree to disagree with the Papa.
Regarding Islam, it also seems to be a practical concern that would be the biggest to an alliance. It seems like their customs discriminate against people born to Muslim families who became Christian. I think it's the biggest obstacle. Jordan and yes even Iran guarantee a Christian place in parliament and have protective laws allowing Christians to worship. I'm sure such protections and laws could be better and enforced better. Plus, Christians have survived for centuries under Islamic rule in many places. I know that the Copts have got it pretty bad, but improvements could be made in principle. My point is just that in some ways an alliance would be possible. Even our church leaders in the 15th century said that they would prefer a Muslim turban to an RC bishops' hat, when confronted with the Crusades.
But such a possibility of an alliance is greatly diminished, and possibly mainly diminished, by the custom attacking people who grow up in Muslim families and want to become Christian. I'm sure there are many other obstacles to an alliance. But it seems like this simple obstacle, just like the idea of RC papal supremacy, seems to be a huge one. To give an extreme example, how could you marry someone if your stepkids would get whooped if they tried to live with you?
It seems that if they would have open discussion about religion and allow simple people to choose what they come to believe is the truth, then it would go a long way to friendship with Islam. Otherwise, if there is no free discussion, questioning, and allowing for exchange, then it is very hard, perhaps harder than doctrine.
Perhaps such an obstacle can be overcome. In the 11th century, Egyptian rulers destroyed many churches and made a rule forcibly converting Christians to Islam, but then changed their mind, allowed the Christians to return to Christianity, and rebuilt the churches. So perhaps some Islamic countries could have a free exchange of ideas, questioning, and allowing people to come to the Truth.
But attacking Christian converts seems like a huge obstacle like Papal Supremacy is.