Three audacious efforts to undermine journalism and perpetuate propaganda in the past week were notable even by the distressing standards of 2017.

It starts, once again, with the 45th president of the United States.

President Trump began a series of tweets last weekend that took aim at CNN International, describing it as “a major source of (Fake) news, and they represent our Nation to the WORLD very poorly. The outside world does not see the truth from them!”

No American president in modern times has so brazenly attempted to undermine U.S. journalists working overseas.

This is not only unseemly, especially with Trump accompanying his blast at CNN with praise for Fox News and its stable of sycophants. It’s corrosive to our democracy, and dangerous for the men and women who are going into unsafe areas in pursuit of stories the people in power would just as soon suppress.

Public condemnation of this nation’s most prominent and reliable television source of international news puts the White House in an odd alliance with repressive regimes. Trump’s tweets came just hours after Russian President Vladimir Putin signed a law to force certain American news organizations to register as foreign agents.

It did not take long for Libyan officials to seize on Trump’s words. CNN recently broadcast an extensive investigation into modern slave auctions being conducted in that country. The report included footage of more than 10 men being sold at an auction near Tripoli.

Invoking Trump’s tweets, the broadcaster Libya 218 suggested “a hidden political agenda” was behind the CNN story.

Clarissa Ward, a CNN senior international correspondent, said for a president to “volubly and publicly” disparage U.S. journalists puts them at risk in areas where hostility toward the news media is no joking matter.

“It’s open season on journalists,” Ward said on CNN.

Consider: Is the American interest really served by constraints on our ability to pursue independent reporting around the world?

Michael Hayden, a retired four-star Air Force general who has served as director of both the CIA and National Security Agency under three presidents, had a strong opinion on the subject.

“If this is who we are or who we are becoming, I have wasted 40 years of my life,” tweeted Hayden, now a CNN contributor. “Until now it was not possible for me to conceive of an American President capable of such an outrageous assault on truth, a free press or the first amendment.”

Speaking of assaults on truth, Trump reaffirmed his role as the commander in chief of fabricated fear when he retweeted three videos from a British ultranationalist group supposedly showing Muslims committing acts of violence. The videos were titled “Muslim migrant beats up Dutch boy on crutches!” and “Muslim Destroys a Statuee of Virgin Mary!” and “Islamist mob pushes teenage boy off roof and beats him to death!”

There was so much wrong with a president sharing such inflammatory material, starting with the fact that British leaders regard the original tweeter, Britain First, as a hate group. As responsible U.S. politicians have noted, Republicans and Democrats alike, this sort of broad-brushed recklessness only alienates Muslims around the world who are critical allies in the war on terror. It also set off a needless spat between Trump and Prime Minister Theresa May.

Perhaps the most important point of all: the dubious veracity of the videos from a vile, racist group. The assailant of the Dutch boy was not a Muslim migrant; the other two videos were 4 years old and absent any context.

White House spokeswoman Sarah Huckabee Sanders defended the Trump tweet as a way to advance a conversation about immigration and border security.

“Whether it’s a real video, the threat is real,” she said.

Think about that for a moment: It doesn’t matter whether the fear-inducing footage is authentic. It’s the effect on the populace that matters.

It sounds like a fairly precise definition of propaganda.

Finally, score one for truth over a scheme to sabotage truth tellers. The Washington Post, which broke the big story about sexual misconduct allegations against Alabama Senate candidate Roy Moore, was approached by a woman claiming to have conceived a child with him when she was 15.

The Post reporters did their research and spotted inconsistencies in her account. The woman abruptly cut off a follow-up interview when challenged about her story and motives, and the newspaper traced her back to the inaptly named Project Veritas, a conservative group that poses subjects in undercover operations to entrap its adversaries — a tactic that is verboten in real journalism.

So the attempt to dupe the Washington Post backfired spectacularly. It ended up validating the diligence and commitment to accuracy of the organization Project Veritas had hoped to discredit.

John Diaz is The Chronicle’s editorial page editor. Email: jdiaz@sfchronicle.com Twitter: @JohnDiazChron