[Volpe]

I'm don't quite get what you are saying, but I also note, you are just saying it without backing it up in anyway.

Why wouldn't it last?

Why can't some members be incompatible with others?

Why must there be a framework to make judgements on others?

The United States is a good example (in a lot of ways) of successful multiculturalism (it's a bad example in some ways as well). But no official language, no restrictions on belief, the only consistant thing is a 'rule of law', is that what you mean by a framework for judging?

[stcredzero]

You can't have a stable multicultural situation where a part of the population can make multiculturalism impossible. Yes, you must have rule of law. You must also promulgate the ideology of multicultural tolerance itself. You cannot tolerate a certain level of intolerance.

[Volpe]

Yes you can. The United states are my go to example for this as well. There are a number of White Supremacist groups in the US, which (mostly due to rule of law) are contained from ruining multiculturalism as whole (they probably have significant local effect). But they still are free to hold their beliefs and practice them (amongst themselves).