Alliances are mostly formed in common interests, so something that could benefit both groups would be segregation and anti-race mixing laws. Race mixing benefits nobody, it takes people of both races who would otherwise raise children of their own race, increasing their race's numbers, and makes them raise children that are neither race, harming both races in the process.

Same thing with segregation.

Another thing it would be based on is our common enemy of the jew.

The muslims would get the jews to stop mingling in their countries in return for getting out of ours and for not mixing / benefiting from our countries. Live and let live. Once the jewish drug lords are out of the picture, latin america might become less shitty to a certain extent. Asians would stop being underrepresented in universities and since asian men are even less likely to get an asian woman in america than a white man getting a white woman, segregation would be a really good thing for them.

Blacks would probably just loose all the gibs, they have nothing to gain from the victory of civilized people, I'm sorry but the actual pure africans in my eyes don't meat the threshold for human. There are however a shit ton of mullatos out there but their numbers in comparison to proper racial groups are still insignificant.