Bill O’Reilly has a message every American must understand: Our country is under attack -- from within.

O’Reilly’s new book, “Culture Warrior,” boldly describes two disparate worldviews that are competing for the very soul of our nation. On one side are the “traditionalists,” those who know that America is a noble enterprise, a beacon of hope and light for the world, and who understand that our belief in God and our commitment to good has made us the greatest nation on Earth. On the other side are the secular-progressives (S-Ps), who see America as imperialistic and intrinsically evil -- and who want nothing more than to sanitize our classrooms and our public squares from the alleged poison of faith.

In an exclusive phone interview, Bill told me that the culture war in which we’re all immersed is “not a political war, but is, at its heart, a social war.” He’s right. And I believe that the battle is also a spiritual one. It transcends politics. It’s bigger than Republican vs. Democrat or conservative vs. liberal, and the stakes are significantly higher than the next election.

Please don’t mistake O’Reilly’s book as just another best-seller from a political pundit (although it is the number-one seller on many lists, and the author is a media powerhouse). “Culture Warrior” is one of those rare books with the ability to inspire the reader to embark on a life-changing mission. O’Reilly affirms the instincts and values of decent Americans, reminding us of the greatness of our country and how it is worth fighting for both at home and abroad.

We live in a defining era -- a brief period in which America’s future is at risk. Will we remain the land of the free and the home of the brave? Or will we allow the secular humanists to hog-tie our rights, and use the schools to drown our kids in their dogma, while we simultaneously succumb to the siren song of malevolence (the anthem of today’s media culture) and become just another hopeless, Godless country in the mold of Western European nations like France?

In my own book, “Home Invasion: Protecting Your Family in a Culture That’s Gone Stark Raving Mad,” I provide evidence of the cultural battle and the harm it’s doing (particularly to our children). I go on to explain how we parents can protect our own homes. But in O’Reilly’s book, he tells Americans how we can protect our country. Of course, the first step is: Know your enemy. Bill names names, and he’s ready to take the heat for exposing the enemies of freedom and decency.

Some of the names, such as the American Civil Liberties Union, will be familiar to you. But even if you’re aware of the ACLU’s agenda -- which boils down to expelling spirituality from the public square -- you’ll find eye-opening details in “Culture Warrior” about this loathsome group that fights, among other things, any mention of “under God” in the Pledge of Allegiance, then defends the “rights” of groups such as the North American Man-Boy Love Association.

O’Reilly exposes how the ACLU’s founder, Roger Baldwin, flatly admitted that “communism is the goal” and added: “I am for socialism, disarmament, and ultimately for abolishing the state itself as an instrument of violence and compulsion.” Of course, the ACLU began concealing their agenda right away, but as O’Reilly proves, nothing has really changed:

“Eighty-nine years later, the ACLU is still using Baldwin’s strategy, wrapping itself in the flag and defending the rights of the ‘folks.’ Unless, of course, the folks are Christians, Boy Scouts, parents who want to know if their underage daughters are having abortions, or concerned Americans who want sexual predators who hurt children held accountable.”