The article splashed across the cover of Saturday’s New York Post seemed designed to enrage Republicans who railed against the Biden administration’s immigration policies.

Under the tabloid-ready headline “KAM ON IN,” The Post, which is controlled by conservative media baron Rupert Murdoch, claimed that copies of a children’s book written by Vice President Kamala Harris were provided at taxpayer expense in a “welcome kit” for unaccompanied migrant children at a shelter in Long Beach, California.

The story whipped around conservative media and elicited denunciations from leading Republicans, including the party chairwoman. A reporter for the Murdoch-owned Fox News, which published its own online article about the claims, asked about it at a televised White House press briefing.

But the claims were untrue. And on Tuesday, the Post reporter who wrote the original article said she had resigned from the paper because of “an incorrect story I was ordered to write,” describing the episode as “my breaking point.”

In fact, no books by Harris were provided by government officials at the shelter, and the sole copy seen in the photograph that The Post published on its front page had been donated through a neighborhood toy and book drive for the migrant children, local officials told The Washington Post.

Despite these facts, The New York Post initially repeated the falsehoods in a follow-up article falsely claiming that “thousands” of copies of Harris’ book had been distributed at migrant shelters.

The rise and collapse of the tabloid’s false accusations about the vice president illustrated the speed at which political misinformation can be weaponized in the modern media environment. The Post later issued brief corrections, but only after its falsehoods had been amplified at face value by leading Republican lawmakers and cable news stars.

“Now they’re forcing taxpayers to buy Kamala Harris’ book to give to those illegal immigrants?” Sen. Tom Cotton, R-Ark., wrote on Twitter on Sunday, adding a link to the Post story; Cotton’s tweet was later deleted.

Tuesday, the author of the original Post article, Laura Italiano, wrote on Twitter that she had resigned from the paper, describing the Harris article as “an incorrect story I was ordered to write and which I failed to push back hard enough against.” She added, “I’m sad to leave.”

Italiano, a veteran Post journalist and longtime chronicler of the New York City courts, is a well-liked figure in the paper’s newsroom. She did not respond to inquiries about her resignation or how the Harris article came to be. Representatives for The Post did not respond to calls and emails tonight.

Her abrupt exit underscored some of the tensions currently roiling The Post, a classic pugilistic city tabloid that was often a vessel for coverage favorable to former President Donald Trump during his term in office.

Murdoch, who spoke frequently with Trump, installed a new editor at the tabloid last month, Keith Poole, who formerly served in a top position at Murdoch’s London paper The Sun. At least eight journalists at The Post have departed the paper recently, including a White House correspondent, Ebony Bowden.

Fox News and The Post, given their shared Murdoch ownership, have long demonstrated a certain symbiosis. (Just last week, The Post ran a gossip item complaining that Glamour magazine was not writing features about female Fox News stars.)

Fox News hosts including Tucker Carlson, Greg Gutfeld and Martha MacCallum discussed the Post article on their programs Monday. Peter Doocy, Fox News’ White House correspondent, cited “a report in the last couple days in The New York Post” before asking Jen Psaki, the White House press secretary, on Monday if Harris “is making any money” from her books supposedly being distributed in the shelters. Psaki said she would “have to certainly check on that,” which The Post described in a follow-up story as Psaki’s having offered “no answers.”

On Tuesday’s “Fox & Friends,” co-host Ainsley Earhardt told viewers that the claims about the Harris book were “not accurate,” citing that morning’s fact-checking column in The Washington Post. Also on Tuesday, Fox News updated its article about the Harris book to note that only a single copy had been seen at the shelter and that it had been delivered as “part of a citywide book and toy drive.”

Fox News has faced criticism in recent days for a different false claim broadcast on the network: that President Joe Biden was planning to restrict Americans’ red-meat consumption under his plan to address climate change. An on-air Fox News graphic declared, “Bye-Bye Burgers Under Biden’s Climate Plan,” setting off a cycle of outrage from conservative commentators.

The claim about burgers and Biden was false. On Monday, Fox News anchor John Roberts told viewers that “a graphic and the script incorrectly implied that it was part of Biden’s plan for dealing with climate change. That is not the case.”

On Tuesday, during an episode of “The Five,” moderate Fox News co-host Juan Williams appeared to acknowledge the recent erroneous reports on his network.

“Last week we had the hamburger story: ‘Oh, Biden is going to take your hamburger!’ ” Williams said. “Or, you know, it’s always — Kamala Harris’ book is being given to immigrants. These stories are false, but the right-wing echo chamber starts going crazy because you can go after a Democrat.”