More than a dozen Senate Democrats are calling on an activist non-profit that backs conservative judicial nominees to disclose its funding sources, questioning its transparency and connections to donors who they say have spent millions on related advertising.

Minority leader Chuck Schumer of New York, Judiciary Committee member Sheldon Whitehouse of Rhode Island, and the other lawmakers labeled the Judicial Crisis Network a “dark money group” in a July 10 letter to Carrie Severino, its chief counsel and policy director.

“[D]espite your organization’s claimed commitment to transparency, JCN continues to conceal the identity of its donors,” the senators said.

Liberal and conservative judicial activists and their legislative supporters have this year amplified their criticism of each other’s donor transparency.

President Donald Trump has made good on his campaign vow to reshape the judiciary with conservative judges. The Republican-led Senate has confirmed more than 120 of his nominees, including Brett Kavanaugh and Neil Gorsuch to the Supreme Court.

Frustrated Senate Democrats largely have been left out of the process through rules and procedural changes in the recommendation and vetting of nominees. They’ve been sharply critical of the influence of outside groups like the conservative Federalist Society over Trump judicial selections. The rightward march of the judiciary under Trump, especially at the high court, is among Democratic talking points in 2020 presidential primary campaigning.

The Democratic letter was signed by 14 lawmakers, including 2020 White House hopefuls Cory Booker of New Jersey; Amy Klobuchar of Minnesota, and Kamala Harris of California. All three are Judiciary Committee members.

Whitehouse, especially, has been a vocal critic of anonymous money backing outside advocacy of Trump nominees, often raising it at confirmation hearings as a corrupting influence.

Judicial Crisis Network on the other side has launched a $1.1 million ad campaign calling for greater transparency by progressive advocacy organizations in the judicial nomination process.

Severino said in a statement that the senators are trying to “distract” the public from the deception of liberal “dark money” allies who are supposedly keeping a secret list of potential judicial nominees for the period following the 2020 election.

“President Trump publicized his list” of judicial candidates, Severino said in the statement. “What are they hiding?”

Schumer, Whitehouse and the others wrote that JCN donors have contributed “tens of millions of dollars” to political advertising in support of Kavanaugh and Gorsuch when they were high court nominees. Kavanaugh’s confirmation process, particularly, was marked by partisan turmoil over sex assault allegations from his high school days, which he forcefully denies.

A review by Bloomberg Law of the latest publicly available federal tax filings shows the largest single donation to JCN in 2017 was for more than $17 million. The Bloomberg Law review also confirmed Senate Democrats’ findings that the Virginia-based non-profit Wellspring Committee Inc. donated more than $20 million in 2016. Wellspring has since terminated its incorporation, Virginia state business records show.

—With Jasmine Han