The so-called “separation of Church and State” is invoked so often it might as well appear on the dollar bill.

John Eastman, law professor at Chapman University, reminds us the phrase isn’t in the Constitution as many people incorrectly believe.

“It’s become part of the common parlance … you go to any city council meeting, [and you’ll hear] ‘You can’t do that. It violates the separation of church and state.’ People believe that’s what the Constitution actually says,” Eastman tells Breitbart News.

Eastman blames Americans United for Separation of Church and State, a group which often goes to court in order to strip religion from public arenas, for keeping the phrase’s incorrect usage alive and well.

Eastman’s new course for Prager University, a learning site now available as an iTunes app, debunks the cultural misunderstanding.

“The Founding Fathers saw religion as indispensable to the moral foundation of the nation they were creating,” he says in the video course.

The phrase first appeared in a brief letter Thomas Jefferson wrote in 1802, the course recalls. In 1947, the Supreme Court referenced the letter in a religious-based decision that laid the groundwork for the modern misuse of the phrase, typically by people on the left.

There’s still hope that Americans will learn the truth behind the phrase and why it is so often misapplied, Eastman says.

“We need to teach it in our schools, let people see the course, insist that our educators in the schools also understand the derivation of the phrase … and hold people accountable for false claims they make,” he says.

For those eager to erase religion from the public space, misusing the phrase can be intentional.

“Some people on the left who know full well the stuff they’re putting out is false,” he says. “If you call them on it, they say, ‘that was 200 years ago, it’s a good thing we progressed from it.'”

Eastman’s legal group, Center for Constitutional Jurisprudence, helps balance the scales of the debate. While Americans United routinely sues city councils and other groups to pressure them to remove God from various institutions, Eastman applies legal pressure in the opposing direction.

“You’re going to get sued either way, so you better be right,” he says of groups involved in religious-based legal skirmishes.

Eastman says the battle against religion is part of a bigger movement, one trying to expand the size and scope of government.Americans are the freest people in the world, in part, because we have private institutions that stand in the way of pervasive government, he says.

“It’s no surprise that the three institutions that counter government most effectively, the church, family and Boy Scouts, are most vigorously under attack,” he says.