The House Oversight Committee is moving to the next phase of its investigation into how the Trump administration is handing out top-secret security clearances: by beginning to issue subpoenas.

After repeated attempts to get the White House to voluntarily provide documents and witnesses to no avail, Oversight Committee Chair Elijah Cummings (D-MD) has sent a letter to White House counsel Pat Cipollone, informing him that his committee will start authorizing subpoenas on Tuesday.

The committee’s planned first subpoena is for a deposition of Carl Kline, a former White House official with a major role in the security clearance process who now works at the Department of Defense. And the move sets up a major confrontation with the Trump White House.

“The Committee respects the President’s authority to grant security clearances,” Cummings writes in the letter. “However, the White House must respect Congress’ co-equal and independent authority to investigate who has been given access to our nation’s secrets, how they obtained that access, the extent to which national security has been compromised, and whether Congress should amend current laws to improve national security and enhance transparency over these decisions.”

The security clearance investigation is one of the first big probes the Oversight Committee started once Democrats took back the gavel in January. Cummings and Democrats think they’ve found a serious scandal that could have grave implications for national security: dozens of high-level officials received security clearances even after career officials recommended rejecting their applications.

These officials included senior advisers Ivanka Trump and Jared Kushner — President Donald Trump’s daughter and son-in-law. Others Cummings flagged include National Security Advisor John Bolton, former National Security Advisor Michael Flynn, former deputy assistant to the president Sebastian Gorka, and former White House staff secretary Rob Porter.

In each case, Cummings is asking for the paper trail leading up to the official being granted a top-secret clearance. And his first subpoena will be aimed at Kline, who directed the personnel security division of the Executive Office of the President. Kline allegedly overruled career-level staff who advised against granting officials security clearances, after red flags were raised about things found in their background checks.

Cummings is no longer asking the White House to comply with these requests; he’s telling them to.

“The White House has refused to produce a single piece of paper or a single requested witness,” he wrote in a letter to Cipollone. “Instead, you claim to have ‘accommodated’ the Committee’s interests by providing a 90-minute briefing on general policy matters and an in camera review of a handful of guidance documents.”

A White House whistleblower has come forward

Even though Cummings says the White House hasn’t complied with his requests, he and his committee aren’t starting from scratch.

The committee has already received significant information from Tricia Newbold, a career official in the personnel security division of the Executive Office of the President, according to an internal committee memo reviewed by Vox.

Newbold has worked in her position for 18 years, under both Republican and Democratic administrations. She’s an important figure because she was one of two specialists who made the determination not to give Kushner top-secret security clearance, according to NBC News.

Newbold already filed a whistleblower complaint against Kline, the White House official Cummings wants to depose first. She had complaints both about how Kline overturned recommendations from her and another career staffer not to give out security clearances to White House officials who had problems with their FBI background checks.

“She explained that she and other career officials adjudicated denials of applications for multiple security clearances that were later overturned by senior officials in order to grant the employees access to classified information,” the Oversight Committee memo stated.

Newbold kept a list of White House officials whose denials were overturned — that list eventually stretched to 25 people, which included two current senior White House officials, government contractors, and other individuals working in the Executive Office of the President. Red flags that came up in these individuals’ background checks included potential foreign influence, conflicts of interest, criminal conduct, drug use, financial problems, and concerning personal conduct, according to the memo.

For the two current senior White House officials, the disqualifying factors that came up in the background checks included potential foreign influence, outside activities (defined as “employment outside or businesses external” to their job in the White House), and — in the case of one official — personal conduct.

Newbold also told the committee about Trump administration policies around personnel that concerned her, including a policy to stop checking the credit of White House applicants during their initial reviews, and sensitive personnel files being left out in the open. She also registered concern around the “unusually high” number of interim security clearances Trump administration officials who handled classified information were working with.

“We were getting out of control with the interim clearances,” Newbold told the committee during a recent interview.

Subpoenas are Democrats’ way of finding out more

So far, Jared Kushner and Ivanka Trump are the two highest-profile officials who got security clearance after staffers like Newbold objected, but Cummings’s list of other officials shows the problem is much bigger.

In Kushner’s case, President Trump personally intervened to ensure he got a clearance in May 2018, over the objections of his top advisers, per the New York Times. Then-Chief of Staff John Kelly and then-White House counsel Don McGahn both reportedly documented their concerns about Trump’s decision in memos. Trump did the same thing with his daughter and White House adviser Ivanka Trump, pressuring Kelly and McGahn to grant her a clearance as well, according to a CNN report.

It’s worth noting that being president gives Trump the legal authority to do what he wants when it comes to security clearances. Each White House gets to decide how it wants to approach the process.

But while Trump isn’t breaking the law by giving Kushner or anyone else a clearance, members of Congress are concerned he is abusing his executive power for nepotistic or corrupt reasons.

But Cummings isn’t just trying to find out about nepotism; he wants to know what national security risks are being posed by the White House disregarding protocol around security clearances.