Senator Cory Booker is for the first time publicly calling on fellow Democrats in New Jersey to end three lucrative contracts to detain thousands of immigrants for Immigration and Customs Enforcement. The position is part of a larger campaign pledge to decriminalize immigration nationwide, but it puts him at odds with powerful Democratic county officials in New Jersey who endorsed him for president.

Booker thinks that the Democratic officials who run Bergen, Hudson and Essex Counties should end their lucrative contracts to imprison immigrants at their county jails for ICE, a spokesperson for the senator said. Booker has specifically raised concerns with officials in Essex County, his home district, about “unsanitary and unsafe conditions” at the jail cited by the Department of Homeland Security’s inspector general, the spokesperson said. His staff has visited the jail, and he supports a pending proposal to create a task force there.

Democratic officials who run the jails in Bergen, Hudson and Essex counties have come to rely on the tens of millions of dollars to each county’s coffers for detaining thousands of immigrants a year. Those contracts have come under scrutiny as the Trump administration jails more immigrants, most of whom don’t have criminal records. County leaders largely defend the contracts, though Hudson plans to end ICE detention by the end of next year.

Officials in the counties did not respond to requests for comment. All of the county executives who oversee the jails — Bergen’s Jim Tedesco, Hudson’s Tom DeGise and Essex’s Joe DiVincenzo — endorsed Booker for president. (He is currently trailing near the back of the pack of the Democractic primary candidates.)

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Earlier this year Booker sponsored the Dignity for Detained Immigrants Act, which he says would mostly eliminate immigration detention and end all ICE contracts with public and private facilities. But beyond that long-shot policy proposal — the Senate is currently controlled by pro-detention Republicans — Booker had avoided calling out his Democratic allies until now.

On the campaign trail in Nevada in July, Booker repeatedly dodged questions when NJTV asked if he thought Essex should end its ICE contract at the county jail in Newark, where he lives. A week earlier Booker had attended a $2,800-per-plate campaign fundraiser hosted by DiVincenzo, one of the most powerful Democrats in the state and a long-time Booker supporter who has defended his county’s approximately $40 million annual ICE contract. Anti-ICE detention protesters yelled at the donors arriving to the event.

At the time, Booker acknowledged raising issues at the jail to DiVincenzo, and the senator said he had a plan to “phase out” detention nationwide.

Last week, Booker introduced a bill that would eliminate the use of solitary confinement — officially known as “segregation” — as a disciplinary measure for ICE detainees who are accused of committing jailhouse infractions. The press release announcing the bill linked to a DHS inspector general’s report about Essex that specifically cited that jail’s abusive practices: Putting detainees in solitary confinement for 23 hours a day before they’re given hearings, and inappropriately using handcuffs and strip searches.

In response to a request for comment about the bill and conditions at the Essex Jail, Booker’s spokesperson told Gothamist/WNYC on Sunday that the senator was concerned about Essex and in fact wants all three county ICE detention contracts in New Jersey ended. He also supports a proposal — expected to be up for final passage by the Essex County board of chosen freeholders next month — to create a task force to monitor jail conditions for both criminally charged inmates and detainees held on immigration violations.

Earlier this year an immigrant was deported after he alleged that he was sexually and physically assaulted in the segregated housing unit at the Essex jail by county corrections officers. Another said he was put in solitary after refusing to be strip-searched. WNYC has also reported on the use of solitary confinement as a means of discipline for ICE detainees at the Bergen County Jail.

New Jersey’s other Democratic senator, Robert Menendez, said last year that he did not support New Jersey counties detaining immigrants. While Booker is the junior senator, he is the state party’s biggest star and most popular Democrat, who has made a name for himself as a criminal justice reformer.

But Booker’s politics have historically aligned with the centrism of New Jersey Democratic power brokers. This position on immigration detention puts him in the left of his party on one of the biggest issues in the country, which he hopes sets him apart in the crowded Democratic presidential field. Even some immigration advocates do not favor New Jersey endings its ICE contracts.

Matt Katz reports on air at WNYC about immigration, refugees and national security. You can follow him on Twitter at @mattkatz00.