"The markers were not sudden at all," said Dr. Lawrence Rosenthal.
[Ads /]
RELATED: FBI warned of violent 'war' at Capitol in internal report issued day before deadly riot: Report
Rosethal joined ABC7's Kristen Sze on "Getting Answers" Thursday afternoon to discuss the markers of the right-wing, Donald Trump supports who stormed Washington, D.C. and also how the movement that inspired the attack compare to members of the Confederacy during the Civil War.
Following the election of Joe Biden, Donald Trump encouraged his supporters with phrases like "Stop the Steal" and urged them to visit Washington, D.C., Rosenthal said.
"Online people talked about creating caravans to come to Washington," he said. "There's no way in which it was a surprise."
He said the people involved in the storming of Capitol have a violent past.
[Ads /]
"They have a long history of playing at the edge of violent and militia-like behavior," Rosenthal said.
RELATED: Enduring 2nd impeachment, President Trump stands largely silent, alone
President-elect Biden is set to take office next Wednesday, but the movement, fueled by white supremacy and anti-government beliefs, according to Rosenthal, won't disappear when Trump is no longer in office.
Rosenthal used the Confederacy as an example as what the U.S. might see after the Trump presidency, referencing an "animated myth" that fueled Confederate solidarity after the Civil War.
"What I think we may be facing, post Jan. 20, is that there will be a new animated myth on the right in the USA," he said. "And particularly troublesome on the militia right and that animated myth is going to be the stolen election."
[Ads /]
He said the Confederacy held on to solidarity even after a loss in the Civil War, and right-wing Americans will hold onto the idea of a stolen election, he said.
"I'm afraid we may be confronting an angry right wing which has an animating myth of the stolen election," Rosenthal said.
Watch the entire interview with Dr. Lawrence Rosenthal in the media player above.
VIDEO: FBI warns of plans for nationwide armed protests next week
FBI warns of plans for nationwide armed protests next week