There is a conservative way to embrace pluralism and diversity. It's to point out that there is a deep strain of pessimism in progressive multiculturalism: blacks and whites will never really understand each other; racism is endemic; the American project is fatally flawed; American structures are so oppressive, the only option is to burn them down.
A better multiculturalism would be optimistic: We can communicate across difference; the American creed is the right recipe for a thick and respectful pluralism; American structures are basically sound and can be realistically reformed.
This is what I believe, but the Republican party's willingness to weaken institutions in the pursuit of power and failure to embrace a thoughtful, principled - and yes - conservative approach to multiculturalism in the public square bolster the argument that the institutions should be swept aside. The Republicans must define themselves as something other than a party against their opponents, as for something rather than against.