Democratic billionaire donor Tom Steyer argued Monday that Republicans' complaints about liberal "mobs" reflect the same rhetoric used by racist Southerners in the civil rights era.

During an MSNBC appearance, Steyer was asked about an ad from the pro-Donald Trump America First Policies PAC depicting screaming and rowdy protesters. "They are voting… Are you?" the ad asks, telling people to vote Republican.

Some of Donald Trump's opponents have vocally protested the administration and Republicans in recent weeks and months, but the media and Democrats have resisted describing their actions as "mob behavior."

"They're picking up on the president's ‘liberal mob' message," MSNBC host Chris Jansing said of the ad. "Can that work?"

"Listen, this is a line that people have been using to put down broad-based protests since the civil rights movement," Steyer responded. "This ‘mob' statement is something that segregationists used to justify strong police actions against completely legal nonviolent protests."

"So I look at this as absolutely another Republican move to try to inflame people, to try to scare people about what is really going on, which is there is a discussion about their failed policies, there is a discussion about where they have gone and why they have discriminated," he continued. "And it is very clear that they can't stand actual conversation. What they have to do is try to scare people, inflame them and get them excited so that they can't focus on the fact that the Republicans have failed."