The ties between several congressional Democrats and Nation of Islam leader Louis Farrakhan have already become a 2018 campaign issue.

Four different Democrats have either attended a private event with Farrakhan — a notorious anti-Semite who describes Jews as “Satanic” — or publicly expressed support for the hate group leader.

In the scandal’s most recent development, three Democratic congressmen were revealed to have attended a private dinner with Iranian President Hassan Rouhani and Farrakhan.

Minnesota Rep. and Democratic National Committee vice-chair Keith Ellison, New York Rep. Gregory Meeks and Indiana Rep. Andre Carson all reportedly attended the dinner, the details of which only became public last week. (RELATED: Three Democrats Attended Private Dinner With Iran’s President And Louis Farrakhan)

In 2015, two years after the dinner with Rouhani, Carson and Ellison visited Farrakhan in a Washington hotel room, Farrakhan said in a 2016 video posted on his Facebook page. Farrakhan blamed Jews in the media for forcing Ellison to distance himself from the hate group leader.

The Daily Caller reached out to spokespeople for both Carson and Ellison to ask if they would deny Farrakhan’s account of their 2015. Neither provided an answer.

Ellison and Carson’s dinner with Farrakhan and Rouhani, as well as their alleged 2015 meeting with Farrakhan, are already shaping up to be a potential drag on Democrats’ 2018 midterm campaigns.

Carson recently cut a minute-long ad for Democratic Indiana Sen. Joe Donnelly’s re-election campaign, a fact that Donnelly may end up regretting. Republicans have slammed Donnelly for Carson’s role on his campaign and have called on him to denounce Carson’s attendance at the dinner and reported meeting with Farrakhan.

Donnelly’s Republican challenger, Indiana Rep. Todd Rokita, slammed Donnelly for his campaign surrogate’s private dinner with the dictator and hate group leader.

“Joe Donnelly must condemn these meetings between his strongest backer Rep. Andre Carson, the leader of the world’s top sponsor of terrorism, and avowed anti-Semite hatemonger Louis Farrakhan,” Rokita said in a statement. “If any Republican had associations like these, Joe Donnelly and the State Democratic Party would call for their resignation.”

The National Republican Senate Committee (NRSC) similarly called on Donnelly to denounce Carson’s actions, referring

“After Mexico Joe’s unpopular vote in favor of the disastrous Iran nuclear deal, it shouldn’t be a surprise that his top campaign surrogate was meeting with the head of the oppressive regime,” said Bob Salera, a spokesman for the NRSC.

“If Mexico Joe won’t immediately denounce Andre Carson, it will prove that he can’t be trusted to keep the United States or our allies safe,” Salera said. (Republicans have taken to calling Donnelly “Mexico Joe” for his family’s manufacturing ties to Mexico.)

Donnelly’s campaign did not return The Daily Caller’s request for comment.

The Republican National Committee similarly went on the offensive against the DNC over Ellison’s leadership position on the committee, demanding an answer for Ellison’s actions.

Ellison, a former Nation of Islam supporter, denounced Farrakhan when in 2006 while running for Congress and criticized media outlets for reporting on his ties to the hate group leader. Now it appears Ellison was close with Farrakhan much more recently than he admitted.

It’s not just Republicans who have expressed alarm about the close ties between Democrats and Farrakhan.

Anti-Defamation League CEO Jonathan Greenblatt, a former Obama adviser, called the three Democrats’ dinner with Farrakhan and Rouhani “extremely disturbing.” Both the Jewish community and the congressmen’s constituents deserve an explanation for their presence at the private event, Greenblatt said.

Another potential stumbling block for Democrats is Illinois Rep. Danny Davis’s public support for Farrakhan. Davis last week praised Farrakhan as an “outstanding human being in an interview with TheDC and said he has regularly met Farrakhan, including at the hate group leader’s home.

“I personally know [Farrakhan], I’ve been to his home, done meetings, participated in events with him,” Davis said.

“I don’t regard Louis Farrakhan as an aberration or anything, I regard him as an outstanding human being who commands a following of individuals who are learned and articulate and he plays a big role in the lives of thousands and thousands and thousands and thousands of people.”