Leading the charge was The Boston Globe, which had issued an appeal for this drive -- accompanied by the hashtag #EnemyofNone -- that has been joined by more than 200 newspapers around the country.
"Today in the United States we have a president who has created a mantra that members of the media who do not blatantly support the policies of the current US administration are the 'enemy of the people,'" the Globe editorial said.
"This is one of the many lies that have been thrown out by this president, much like an old-time charlatan threw out 'magic' dust or water on a hopeful crowd," it added in a piece entitled "Journalists are not the Enemy."
Trump's treatment of the press is also encouraging strongmen such as Vladimir Putin of Russia and Recep Tayyip Erdogan in Turkey to treat journalists like enemies, the Globe argued.
The coordinated effort comes amid Trump's persistent claims that mainstream media outlets that publish articles critical of him are churning out "fake news."
Free press advocates argue that Trump's efforts threaten the role of the news media as a check against abuse of power in government and imperil the constitutional First Amendment guarantee of freedom of the press.
The New York Times, one of the most frequent targets of Trump's criticism, ran a short, seven-paragraph editorial under a giant headline with all capital letters that read "A FREE PRESS NEEDS YOU" and with the statement that it is only right for people to criticize the press, say, for getting something wrong.
"But insisting that truths you don't like are 'fake news' is dangerous to the lifeblood of democracy. And calling journalists the 'enemy of the people' is dangerous, period," the Times wrote.
Across the country, other papers joined in, defending their place in society -- from upholding the truth to simply saving people time.
"At a practical level, we journalists sit through boring government meetings and learn about public school financing formulas, so you don't have to," said The Arizona Daily Star. "It's not as lofty a statement as the First Amendment, but it serves."
- Cannot sit back -
Free press advocates say Trump is a real threat to the role of the press.
"I don't think the press can just sit back and take it, they need to make their case when the most powerful man in the world tries to undercut the First Amendment," said Ken Paulson, a former editor-in-chief of USA Today who heads the Newseum's First Amendment Center and is dean of communications at Middle Tennessee State University.
But Paulson questioned whether editorials would be effective.
"The people who read editorials don't need to be convinced," he said. "They are not the ones trying to shout you down at presidential rallies."
In the face of a White House onslaught, Paulson said the media needs a broader marketing campaign to highlight the importance of a free press as a core value.
The campaign also faces the potential for galvanizing supporters of the president around the notion that the media is out to get him.
"The media are organizing an ever more deliberate and public attack on @realDonaldTrump and on the 'deplorable' half of the country who support him. And the media wonders why we think they are 'fake news?'" tweeted Mike Huckabee, a former Republican governor who is a Fox News commentator.
But media rights advocates say the stakes are too high to allow the president's claims to go unchecked.
Some say Trump's comments have incited threats against journalists covering his events, and may have created a climate of hostility that opened the door to violent attacks like a deadly one in June against the Capital Gazette in Annapolis, Maryland.