Activists are urging the Republican Jewish Coalition to abandon its support for presidential hopeful Donald Trump as the presumptive GOP nominee prepares to secure his party’s backing this month in Cleveland.

Social justice group Bend the Arc launched a petition last week calling on Republican Jewish Coalition Director Matt Brooks to walk back the RJC’s endorsement after Mr. Trump used a Star of David in a tweet calling Democratic contender Hillary Clinton the “most corrupt candidate ever.”

While Mr. Trump’s tweet immediately raised eyebrows from Democrats and Republicans alike, Bend the Arc said the social media post was only the most recent incident in a series of missteps that should concern Jews. Its petition, first reported by The Jerusalem Post on Saturday, suggests the scandalous Twitter remark was merely the icing on the cake, as far are the activists are concerned.

“We’ve seen this before from Trump and his campaign staff. This isn’t about a single tweet. This is about a deplorable pattern of racist behavior that is fueling Trump’s bid for the White House, a pattern that started on the day he launched his campaign and called Mexican immigrants ‘rapists’ and ‘murderers,’” the group wrote.

“Many Jewish Republicans — who have a unique power to influence Trump’s campaign and put a stop to this hatred — have demanded that Trump change his ways. But the most powerful Republican Jewish group of all, the Republican Jewish Coalition (RJC), has been silent.”

The petition calls on Mr. Brooks to withdraw support for Mr. Trump “and his platform of bigotry,” effectively rescinding an endorsement first handed out by the group in May.

“Throughout the course of this long campaign among Republicans there has been unity in the belief that Hillary Clinton is the worst possible choice for commander in chief,” the coalition said then.

“For a national Jewish group to continue to support him is unconscionable,” Bend the Arc responded last week. “As a Republican group, the RJC has the ability to pressure his campaign to cease being a megaphone for hate. As a Jewish group, they are morally obligated to do so.”

In addition to the petition put forth by the RJC, Jewish groups including the Anti-Defamation League and Hebrew Immigrant Society signed their names to a letter this week condemning the use of anti-Semitic rhetoric in the White House race, albeit without evoking Mr. Trump by name.

“We share a belief that public figures, including those who aspire to hold elected office in service to people of all races and religions, have a responsibility to forcefully and unequivocally condemn these dangerous phenomena,” it read in part. “We object to hurtful characterizations of entire ethnic groups as criminals. We are pained by anti-Semitic epithets hurled at Jewish Americans on social media.”

Mr. Trump’s 6-pointed-star-bearing tweet was deleted from the businessman’s account within two hours of being published last Saturday. He has nonetheless defended the post in the days since, and blamed the media for misinterpreting the image.

“The sheriff’s badge – which is available under Microsoft’s ‘shapes’ - fit with the theme of corrupt Hillary and that is why I selected it,” Dan Scavino, social media director for the Trump campaign, said in the statement. Ed Brookover, an adviser for Mr. Trump, told CNN on Monday that “there was never any intention of anti-Semitism.”