American conservative commentator and author Patrick Joseph "Pat" Buchanan said he believes the status of the United States as a "Christian nation" is on the decline, even as he noted that churches have become irrelevant to today's youth.

"The decline in Christian identity is greatest among the young," Buchanan wrote in a recent column for Townhall, citing statistics from the Pew Research Center. "While 85 percent of Americans born before 1945 still call themselves Christians, only 57 percent of those born after 1980 do."

He expressed fears that Christianity in the US might suffer from the same fate that befell Europe after predominantly Catholic Ireland legalised same-sex marriage in a landslide vote.

He blames several causes as to why the US is slowly becoming a "de-Christianized America."

"High among them is the Supreme Court, which, since the Earl Warren era began, purged Christianity from all public schools and the public square – and has been met with a puzzling lack of resistance from Middle America to the secularist revolution being imposed upon it," Buchanan wrote.

He also pointed the finger at the "anti-Christian elite" for assaulting "Christian beliefs and morality" through "the arts, elite universities, popular culture, and the media."

Without Christianity, noted Buchanan, there will be more marriages that end in divorce, a lower birthrate, more children born out of wedlock, and soaring crime rates. And once Christianity dies, it will be replaced by individualism, materialism, and hedonism.

"Historically, as the faith dies, the culture and civilization to which it gave birth die, and then the people die," Buchanan wrote. "And a new tribe with its own gods comes to occupy the emptying land."

Christianity played an important role in shaping up the US and Western culture, he recalled.

"Christianity was the founding faith of the West," he wrote. "That faith and the moral code and culture it produced once united this disparate and diverse nation and civilization."

Buchanan wonders what would happen to America now that Christianity appears to becoming more and more irrelevant to its people.

"As Christianity fades away and the moral code and culture it generated recede into irrelevance, what will hold us together?" Buchanan asked.