what's the new basis of western civilization?

Through immigration of non-white races, the concept of racial purity and superiority - the same concept that keeps other civilizations proud and strong - is being largely destroyed, along with Christianity, in all western nations.

In place of Christianity and racial purity, the new western nations espouse:

racial diversity;
cultural diversity;
religious diversity;
equal opportunity,
affirmative action;
political correctness,
globalization;
open immigration; and
extensive welfare and human rights programs.

These factors most definitely separate and divide western civilization from other civilizations - in that no other civilization would dream of implementing such crazy, liberal ideals - but what is the cohesive force that keeps western civilization together?

What is the essence, what is the unique feature of the new western civilization that distinguishes it from other civilizations and protects it from extinction?

Diversity? How can diversity be a cohesive force?

In the event of war with a civilization from which most immigrants came, what side would they be on?