Rep. Jan Schakowsky (D-IL) rescinded her endorsement of Cook County Commissioner Donna Miller, who is running in a Democratic congressional primary in Illinois’ 2nd District, over support Miller is reportedly receiving from AIPAC-aligned forces.

Miller has not been endorsed by AIPAC and neither the group nor its super PAC are publicly spending any money in the district. But it’s widely rumored in the Chicagoland area that pro-Israel forces are backing a new group, Affordable Chicago Now, that’s spending about $900,000 on behalf of Miller’s campaign. Schakowsky also said Miller is accepting individual donations from AIPAC supporters.

Schakowsky’s reversal is a notable step in a campaign by progressives to make even perceived ties to AIPAC or any individual donors who have supported the pro-Israel group toxic within the Democratic Party — even if their support for a candidate isn’t coming through AIPAC.

“Illinois deserves leaders who put voters first, not AIPAC or out-of-state Trump donors,” Schakowsky said in a statement. “I cannot support any candidate who is funded by these outside interests.”

It’s not clear how much influence Schakowsky’s endorsement will have outside her district, given her limited profile in a majority-Black district — as opposed to her wealthy, progressive Lakefront constituency. But it comes amid a broader campaign by left-wing activists in the Democratic Party to turn AIPAC and its donors into a burden for Democratic candidates.

The Illinois primaries are set to be a major test of pro-Israel donors’ influence and political instincts after a high-profile fumble in New Jersey, in which the group’s spending was seen as helping to elevate a far-left anti-Israel candidate.

Former Rep. Tom Malinowski (D-NJ), the target of AIPAC’s spending in New Jersey, in an op-ed released on Thursday, said that Democratic leaders should “collectively … refuse [AIPAC’s] support” and reject its endorsements and assistance — arguing that the group’s biggest donors are Republicans, even while acknowledging most AIPAC members are Democrats.