(CNN) Most pastors say they preach the truth. The Rev. William Barber also delivers sermons on another topic: "the trick."

The trick is Barber's term for something that he describes as a weapon of mass distraction. It stymied the leaders of the populist movement in late 19th century. It vexed union leaders who promoted workers' solidarity. The Rev. Martin Luther King Jr. died trying to beat the trick.

The trick is when white politicians persuade poor white working class people that the source of their pain is people of color, immigrants and other scapegoats, says Barber, who rose to national fame after helping lead Moral Mondays, a social justice movement formed in North Carolina.

"You have to show them the trick," says Barber, his rich, baritone shifting into preaching mode when asked how he would address this challenge.

Protests like this one in 2014 are planned for Memphis and dozens of other cities on Monday.

"The majority of people in this country who are poor are white people. You have to undermine the trick and say, 'Listen, you want a living wage, but the people you voted for don't want a living wage. You're upset that you don't have health care. Guess what, black and Latino people aren't your problems. It's the people who are voting against health care.' "

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