SHERMAN, TEXAS -- Religion in politics: the struggle to balance the two has gone on for centuries.

Today, a Georgetown University professor revealed his eye-opening research on the topic to Austin College students.

Dr. Jacques Berlinerblau says he's concerned about politicians using religion for political gain. He says both President Obama and Mitt Romney have cited the Bible on the campaign trail.

Berlinerblau says this could actually be threatening our country's religious freedom.

"Just because the majority wants it for heartfelt and honest reasons doesn't mean that the government has to grant that right," Berlinerblau said.

Berlinerblau is the author of "Thumpin' It: The Use and Abuse of the Bible in Today's Presidential Politics."

Tuesday at Austin College, he demonstrated how in the past 30 years, religion has played a bigger role on the campaign trail.

"We've seen an uptick of the use of religious imagery, especially in presidential politics and state-wide politics," Berlinerblau said.

He says an example of that is Governor Rick Perry's prayer rally in Houston that drew tens of thousands.

"I think it would've been unfathomable 30 years ago, or in the 70s or the 80s. This was really a line that an American politician, especially an American politician seeking national office, would've never crossed," Berlinerblau said.

Berlinerblau says the master of religious rhetoric is George W. Bush, but it's not just Republicans citing religion. Since John Kerry's defeat in 2004, Berlinerblau says Democrats have used more religious imagery, as well.

"A politician will lift three or four words from the scriptures that his or her base is very, very familiar with, without telling the country that the transaction has just occurred," Berlinerblau said.

Local pastor and Democratic Party Chairman Lander Bethel says this use of religious lingo concerns him.

"It's almost like using it as a photo ID to say, 'I'm a member of the club, you can trust me,'" Bethel said.

Students who were there say it was refreshing to get more insight on religion's role.

"Highlight what's going on, to actually show them what's actually being said in the election," student Sathya Kikkeri said.

Berlinerblau says we should expect another ten to twenty years of this religious-imagery trend.

He's adds that the religious tones impact the campaign more than actual policy making in office.