The nation of immigrants doesn't need immigrants anymore. We are perfectly capable of providing our society with everything it needs without additional human resources from abroad. Quotas for educated and skillful workers, scientists and artists from Europe and Asia will contribute a lot to American nation. They are well-bred and perfectly compatible with our culture and Western social values.
But what's the point of welcoming hordes of third-world refugees? Most of these people know nothing about American life, our standards and our laws. Their kids will never know horrors of Iraqi and Syrian life and will never be grateful to us.