Has "toughen up" turned into code for "beat up progressive people of colour?"

In a damning series of video clips from Donald Trump's rallies, Rachel Maddow highlights how the Republican frontrunner's claim that he doesn't "condone violence" simply doesn't add up.

The footage suggests that well before violence broke out at Trump rallies in Chicago and St. Louis — both cities with racial tension after police shootings of black teens —Trump repeatedly urged fans to show people the "consequences" of protesting, promising financial aid if anyone got in legal trouble beating someone up at his events.

"If you see somebody getting ready to throw a tomato, knock the crap out of them, would you? Seriously... I promise you I will pay for the legal fees. I promise," Trump said at a rally in Iowa on Febraury 1.

From there, his rhetoric escalates.

Maddow points out that Trump seemed to target cities that were "tinderboxes" around issues of race, racism and police violence —St. Louis, Chicago and Cleveland—and refused to cancel his rally in St. Louis despite concerns that racially charged violence may break out (it did).

Maddow showed how Trump encouraged his supporters to "toughen up" against protesters at his rallies. In past weeks, Trump is shown pumping up the crowd up whenever a protester is ejected, sometimes shouting "USA! USA!" In his most recent rally, right after the violence in Chicago, he suggests his detractors (many of them visible minorities) "contribute nothing" and are "bad for the country," hinting that it would be morally justifiable — even patriotic — to give such people a beating.

"That was Donald Trump's display of leadership and calming the waters," Maddow comments in disbelief.

She shows a video clip of Trump's divisive speech against those who speak out against him:

"You know, part of the problem... is nobody wants to hurt each other anymore right? They're being politically correct...the protesters they realize it, they realize there's no consequences to protesting anymore.

"Our country has to toughen up, folks. We have to toughen up. These people are bringing us down. Remember that...These people are so bad for our country, you have no idea, folks. You have no idea. They contribute nothing, nothing....get him out, troublemaker. Hurting this country, folks. Hurting this country."

As people screamed "USA!" behind him, Trump taunted the protester, urging him to go home and get a job.

"These are not good people. These are not the people who made our country great," Trump said. "These are the people that are destroying our country."

Although Trump claims to "love everybody," his rallies often inflame hatred against those who protest at his events.

In Nevada on February 22, Trump nostalgically reflects on a golden era when liberal protesters would get injured at political rallies.

"I love the old days. You know what they used to do to guys like that when they were in a place like this? They'd be carried out on a stretcher, folks… I'd like to punch him in the face, I'll tell you."

In North Carolina, where Trump has a big lead over rival Ted Cruz, he suggests that if protesters were treated "very, very rough," they would likely be discouraged from future activism.

Trump support and right-wing media

These days, Trump rallies draw a large crowd, some attracting upwards of 30,000 people, eclipsing events by his GOP rivals Marco Rubio and Ted Cruz. But while Trump mocked former presidential candidate Mitt Romney for losing his bid 2012, Trump himself was also unofficially running four years ago, centering his campaign on the fringe idea of Obama's birth certificate.

He "bowed out" of that race in May 2011, saying he wasn't yet ready to leave the private sector.

Trump bragged that he may one day win the GOP nomination and the general election if he made a serious effort, but many at the time didn't believe him, and joked about his ideas.

What changed?

Some might argue that the creation of a mainstream public receptive to Trump's rhetoric was caused in part by by right-wing personalities like Rush Limbaugh and Bill O'Reilly, who routinely criticize immigrants, African Americans, feminists, the poor, and Democrats on their show.

While such shows have been around for decades, eight years under America's first black president, Barack Obama, made white Americans for the first time "hyperaware" and "anxious" about their status, writer Jamelle Bouie theorizes in Slate.

In a recent documentary, The Brainwashing of my Dad, filmmaker Jen Senko explores how her own father, a mild-mannered former Kennedy Democrat, turned hateful against minorities after years of listening to right-wing talk shows.

Senko says she discovered in her research that other people across the U.S. had family members who had undergone a similar, radical change.

One of the people interviewed in Senko's film expresses bewilderment over how his mother, a moderate Republican, became more extreme as she listened to Fox News.

"It became like the Democrats were not just wrong on the issues, but they were bad," he said. "They were evil.... She'd never say things like that before. It was harder edged. It was more absolute. It's like the world was divided up into good people and bad people, and they (progressives) are the bad people. It's not just a disagreement, politically."