I heartily recommend Herbert London’s book, America’s Secular Challenge: The Rise of a New National Religion.
London writes:
Robert Frost once said that a liberal was someone who refused to take his own side in an argument. Radical secularism, bolstered by the relativistic teachings of multiculturalism, elevates that foible into a philosophy of life.
And,
Culture matters. Decency, sacrifice, and hedonism do not emerge spontaneously, and a great nation cannot retain its greatness while wallowing in a depraved culture.