The big thing is not so much race, but culture. If we can "convert" the Mexicans, or the Chinese, or the Indians to our European-American culture and way of thinking, the US will continue to be the most stable, successful, prosperous, humane, and free civilization in the world. The melting pot is intended to break down the barriers that defined our ancestors overseas, such as religion, race, and nationality, and create a united "American thought".
What, exactly, is "American thought" and European-American culture? Please be specific.
Which predominantly white countries do you believe should replace their white majorities with melting pot experiments? All of them or just the US?