A new study is comforting to some, downright alarming to others. Pew Research, the highly-respected polling outfit, questioned tens of thousands of Americans about their religious faith and affiliation.

The most striking finding: Christianity is in a steep and secular decline, pardon the pun. Only about 70% of Americans now identify themselves as Christians, a drop of 8 percentage points from just seven years ago.

So, where did all those missing Christians go? They have not converted to Judaism, Hinduism, Buddhism, or any other religious "ism." No, they have basically dismissed religion altogether.

The biggest increase in the survey was among Americans who describe themselves as atheist, agnostic, or "nothing in particular." Pew researchers characterized the trend as nothing less than "astounding."

That cheering you hear is coming from the left, home to "progressives" who agree with Karl Marx's odious comparison between religion and opium. Marx, whose theories led to more deaths than anyone in human history, added this: "The abolition of religion as the illusory happiness of the people is required for their real happiness."

One slight problem is that Marx was dead wrong, as he was about pretty much everything. Social scientists universally find a powerful correlation between belief in God and worldly contentment.

But when a nation loses its religious bearings, there is something far more important at stake than human happiness. It's illustrated in a famous quote often attributed to the brilliant British writer and thinker G. K. Chesterton, who converted to Roman Catholicism in his late 40s.

"When men choose not to believe in God," he reportedly said, "they do not believe in nothing ... they become capable of believing in anything."

At the extremes, Chesterton's warning was illustrated by the Nazis, who replaced God with the god of racial purity, and the communists, who worshipped at the altar of radical egalitarianism.

Of course, our own anti-religionists are much more benign. They often proclaim their deep faith in environmentalism, wealth redistribution, the welfare state, feminism, or the eternal pursuit of individual gratification.

These trendy causes and movements come and go, but the human need to believe in something - anything - is a constant throughout history. And the greatest, most free, most optimistic nation ever created was founded by men who firmly believed in Judeo-Christian principles.

Scholars debate whether Washington, Jefferson, Franklin, and the others were deeply religious men, and whether the Constitution omitted God for a reason. That may be interesting to academics, but what really matters is that the Founding Fathers formed a nation uniquely based on Christian principles.

The present decline of Christianity is good news to the swells. You know, the Hollywood types who routinely mock the faithful, and the editorial page writers who have never set foot in a church except when taking in the sights on their European vacations.

Let's face it, atheism is kind of chic. Book stores and Kindles feature popular authors who declare that "God is Not Great," and "God is a Delusion." The secular press heaps praise on these books, while the authors are in great demand on the talk show circuit.

But it's an ominous trend to those who believe America has a special and exceptional place among nations. The Judeo-Christian traditions that have been an integral part of America's greatness are withering away. That is not a cause for celebration, but for deep mourning.

John Lennon famously urged us to "imagine no religion," and touted the notion of "all the people living for today." Well, that dream of the secularists is slowly coming true, and millions of Americans are in fact living for today.

It is not a pretty sight to watch religious faith withering before our eyes, being replaced by rank self-gratification. Pardon the expression, but may God help us.