Julian Zelizer is a professor of history and public affairs at Princeton University and author, with Kevin Kruse, of the new book "Fault Lines: A History of the United States Since 1974." Follow him on Twitter at @julianzelizer. The opinions expressed in this commentary are his own. View more opinion at CNN.

(CNN) The media have spent several days covering the noxious chant -- "Send them back" -- that broke out at President Donald Trump's North Carolina rally. The chant was inspired by a tweet from the President, saying that congresswomen Ilhan Omar, Alexandria Ocasio-Cortez, Ayanna Pressley and Rahida Tlaib should "go back" to the "broken and crime infested places from which they came."

Critics rightly condemned the President for encouraging this racist message among his loyal base. No longer shy about calling out Trump's use of racist tropes, politicians and reporters came down hard on his injection of dangerous rhetoric into his reelection campaign. And though Trump later said he didn't like the chant, he did nothing to stop it.

But here's the problem: This kind of nonstop coverage is exactly what the President counts on. Since Trump declared his candidacy, so many reporters have endeavored to call out the President when he lies or distorts the facts. And though they've been more discerning in trying to sift the serious stories from the daily chaos, they still have not figured out how to handle the ways he manipulates the 24-hour news cycle to promote political messages meant to provoke and incite.

Regardless of how news stories evaluate what the President or his supporters have said, the message itself keeps circulating in the public square. From his tweet to the subsequent chants to the endless coverage about the rally, voters in Trump country are hearing "send them back" over and over again, wording with a long history in racist and nativist discourse and one now targeting four prominent women of color. Although analysts are disputing what impact his white nationalism will have in the election, writers like Nate Cohn and David Wasserman have argued that these messages might strengthen the advantages that he has in the Electoral College.

Ever since the start of the television age, politicians have understood that the news coverage of controversial messages can do more than anything to advance a single cause.

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