MSNBC Politico says it was a mistake for reporter Ken Vogel to have sent the DNC an article in advance.

NEW YORK ― Politico acknowledged Sunday that it was a “mistake” for one of its top reporters to send the Democratic National Committee an advance copy of an article while emphasizing there were no substantive changes made to the piece prior to publication.

A May 2 article by Politico’s Ken Vogel and Isaac Arnsdorf ― “Clinton fundraising leaves little for state parties” ― has come under scrutiny since WikiLeaks published over 19,000 internal DNC emails on Friday.

In an April 29 email thread, DNC national press secretary Mark Paustenbach shared Vogel’s detailed questions with others working to coordinate a response to what would be an unflattering story about fundraising efforts. Paustenbach also spoke to the Clinton campaign that day in preparing the DNC’s pushback, according to the emails.

On April 30, Paustenbach told DNC Communications Director Luis Miranda that he’d received the story in advance. “Vogel gave me his story ahead of time/before it goes to his editors as long as I didn’t share it,” he wrote. “Let me know if you see anything that’s missing and I’ll push back.”

WikiLeaks Sharing articles with sources in advance is generally frowned upon in newsrooms.

Journalists are expected to ask questions of those they write about prior to publication, but sharing entire stories in advance is generally discouraged in newsrooms.

On Sunday, Politico spokesman Brad Dayspring told The Huffington Post in an email that sharing stories with sources isn’t standard practice.

“Politico’s policy is to not share editorial content pre-publication except as approved by editors,” Dayspring wrote. “In this case the reporter was attempting to check some very technical language and figures involving the DNC’s joint fundraising agreement with the Clinton campaign. Checking the relevant passages for accuracy was responsible and consistent with our standards; Sharing the full piece was a mistake and not consistent with our policies. There were no substantive changes to the piece and in fact the final story was blasted out by the both RNC and the Sanders campaign, and prompted Politifact to revise its rating on the issue in question.”

Vogel, Politico’s chief investigative reporter and author of the 2014 book Big Money, is regarded as one of the top journalists on the politics and money beat. He’s reported critically on fundraising across party lines and the article in question wasn’t one the DNC or the Hillary Clinton campaign would have liked to see in print. Vogel and Arnsdorf reported that only 1 percent of $61 million raised by the Hillary Victory Fund ― a group comprised of Clinton’s campaign, the DNC and 32 state party committees ― had gone to state parties.

Two days later, Politifact revised its rating on a claim from actor and Clinton supporter George Clooney that “the overwhelming amount” of money raised at a Clinton fundraiser would go to down-ballot Democrats. In light of Politico’s reporting, the fact-checking organization changed its assessment from “Mostly True” to “Half True.”

As Vogel and Arnsdorf wrote at the time, allies of Sen. Bernie Sanders (I-Vt.) were concerned with the joint fundraising arrangement. “They see it as a circumvention of campaign contribution limits by a national party apparatus intent on doing whatever it takes to help Clinton defeat Sanders during the party’s primary, and then win the White House,” they wrote.

The WikiLeaks trove, more broadly, has reinforced long-running perceptions among Sanders supporters that the DNC was assisting the Clinton campaign during the Democratic primary. DNC Chair Debbie Wasserman Schultz announced her resignation Sunday in response to the fallout from the leak.

Though the Politico story wasn’t positive toward the DNC, the courtesy Vogel extended to the party has been seized upon as evidence of liberal media bias by some conservatives media figures, such as radio hosts Laura Ingraham and Mark Levin and Republican pollster Frank Luntz.

Dear Media: If you're wondering why conservative Americans don't trust you, please see @Politico reporter @KenVogel. https://t.co/FTVsBt2D87 — Frank Luntz (@FrankLuntz) July 22, 2016

The Republican National Committee, too, has turned a spotlight on leaked emails involving Politico.

On Saturday, The Republican National Committee blasted a Business Insider story on Vogel’s emails to its press mailing list and communications director Sean Spicer charged that the reporter allowed the Democrats “to edit” his stories in advance.

Disclosure: The reporter worked with Vogel at Politico from November 2007 to March 2010.