There are territorial disputes between Muslim nations but there are also such disputes amongst Europeans. There are differences on policy between the US and EU , even, but they still come to a settlement of some sort.
Tribal/Sectarian lines are the biggest hinderance to such an alliance, but these can be overcome too. In a Muslim 'EU'/NATO, the powerful Muslim nations would lead such an alliance and micromanage the sectarian/tribal differences. We are looking at :
1.) Saudi Arabia
2.) Iran
3.) Turkey
4.) Pakistan
5.) Egypt
6.) Algeria
7.) Indonesia
8.) Qatar
9.) Kuwait
10.) UAE
etc.... I probably missed a few so feel free to pitch in.
There must be social/political/economic cooperation. While the more powerful nations contribute to creating a humanitarian fund to help the less fortunate in impoverished areas. They do not need to be on the same page on everything but there must be a settlement in conflict hot zones such as Yemen, Syria. The Union must at least diplomatically and financially support popular causes such as Palestine, Kashmir, etc.... To keep them on the radar. Military solutions to such causes are not realistic at the moment.
Turkey/Qatar has influence over the Muslim Brotherhood and can cause shift to their agenda to begin preaching for an integrated region, that despite big differences among them, can at least pause the culture war in the region, setting change to permantely eliminate it in future.
Saudi Arabia likewise has influence over Arab bloc/Salafi bloc. And can do same.
Iran has the influence over Shia bloc and can reign its proxies in.
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Obviously people will say it's because of US influence. Those that say that also must consider Russian influence. The real reason is people in region do not trust each other. Extending your hand is met with being taken advantage of, by a bloc that wants it all and does not believe in sharing.
I don't understand why we as Muslims can be so selfish and greedy. What is wrong with making some sacrifice in geopolitical interests for greater good of people of region?
If there are any other factors you think prevents a formation of Muslim EU, please share. I can think of one more:
1.) Nations aren't developed enough, and do not know what their potential is, and what they can bring the to the table, especially with oil being phased out in coming decades.
^^
European nations were more developed an each offer something unique. Muslim nations have not realized their potential , despite some of them like Turkey, Iran, Indonesia, and maybe Saudi Arabia offering more in some sectors.