Presidents and presidential candidates try to manipulate public opinion whenever they consider press coverage embarrassing, unhelpful or worse.

President Trump and his White House have succeeded beyond others, using abrasive rhetoric to excoriate the press, gin up core supporters and convert the undecided.

“It is frankly disgusting the press is able to write whatever it wants to write,” he said early in his presidency, setting the stage for frequent tirades against news organizations and journalists during his first 1,000 days in office.

Never mind the news media’s purpose in America’s democracy is to hold the president and other public officials accountable. That’s not the case in China or Russia. So why should it matter in the USA?

Trump’s favorite characterizations of the press echo those of despots: “Enemies of the people” … “fake, disgusting” … “traitors” … “sick people.”

He brooded recently about perhaps starting a government news outlet to counter unwanted coverage of his offbeat administration. Twitter apparently isn’t sufficient.

The harshness is not without effect.

Public opinion polls among voters who embrace Trump’s reign buttress his power of propaganda, schoolyard taunts included. The vast majority firmly believe the press cooks the news to make the president look unfit for the Oval Office. Their conviction is ceaselessly reinforced by conspiracy theorists and disinformation marauders on the internet and other forms of commications.  

That’s why Trump’s so spontaneously available to reporters on the South lawn, Rose Garden, Oval Office and other impromptu settings yet eschews formal White House press conferences. Absolute control over the haranguing is necessary.

His utmost believers get the message. Insult the enemy press. Rip the daylights out of journalists. Shred the First Amendment’s press clause. Spare no antics.

No surprise then that a meme video of Trump’s image graphically slaughtering his antagonist targets in the “Church of Fake News” turned up last weekend at a conservative political gathering held at Trump’s National Doral Golf Club near Miami.

The conference’s stated purpose: support free speech and free association. The vile video put both of those noble principles to an extreme test only nut jobs can embrace.

To briefly summarize, the graphically violent clip featured a massacre scene where a dark suited man with Trump’s head superimposed on the body walks through the church brutally assaulting and shooting churchgoers wearing the faces of his political detractors and the logos of NBC, CNN, PBS, Washington Post, New York Times and other news outlets.

American Priority, the group sponsoring the conference, denounced the video as an unauthorized entry in the event’s “meme exhibit” and said it was not associated with the organization “in any official capacity.”

Trump, who did not attend the conference, also condemned the anonymously created video.

Unofficial or unauthorized, the video’s bloody meme adaption from a church scene in the 2014 film “Kingsman: The Secret Service” sent a horrifying message of violence against journalists and politicians who Trump often degrades in public.

One can only hope the “Church of Fake News” video jolts the president into realizing his war on the press and other perceived enemies could lead to terrifying consequences.

Shameless language may appeal to his loyalists but it will also breed dangerous discontent among fanatics between now and the 2020 election.

Bill Ketter is senior vice president of news for CNHI newspapers. Reach him at wketter@cnhi.com.