Senate Judiciary Chairman Chuck Grassley is amping up his investigation into Hillary Clinton's email setup and the special work status of one of her top confidantes — just as the Democratic presidential front-runner's allies are accusing Grassley of using his oversight authority to hurt her campaign.

Grassley (R-Iowa) took two new steps last week. On Wednesday, he issued a letter to former Clinton aide Heather Samuelson, who screened Clinton's emails as secretary of state to initially determine which ones would be turned over to the government and made available publicly, and which ones were deemed private and would later be deleted. Among other things, the missive, obtained by POLITICO, asked what level of security clearance Samuelson had at State; several hundred of Clinton's emails, which she routed through a private server, have since been deemed classified.


Then, on Thursday night, Grassley blocked the nomination of a top-level Obama State Department nominee, Thomas Shannon Jr., to be undersecretary of state for political affairs. Grassley is seeking documents from State in his long-running investigation of a job arrangement for top Clinton aide Huma Abedin. Her designation as a "special government employee" allowed Abedin to work as an adviser to Clinton at State at the same time she consulted for a private company with close ties to the Clinton family.

Grassley, a 35-year veteran of the Senate who already has held up a number of other State appointees over what he views as the department's lack of cooperation with legitimate congressional inquiries, is plainly frustrated.

“Two-and-a-half-years ago I began a broad inquiry into the government’s use of special government employee programs. …Two and a half years have passed ... and the State Department has still not produced the materials I have requested,” he said on the Senate floor Thursday evening. “The Department of State’s refusal to fully cooperate with my investigations is unacceptable."

The State Department responded that Grassley's "mounting requests ... contained nearly 200 detailed questions and 65 unique document requests" and are overwhelming the department's resources.

"We have responded in 16 formal letters and many briefings, calls and emails," spokesman Alec Gerlach said in a statement. "The Department is committed to working with the Committee and providing responses as quickly as possible, but the growing effort needed to accommodate these requests is overwhelming the resources we have available."

The news comes as Democratic senators join Clinton supporters from the outside group Correct the Record in blasting Grassley's efforts as a politically motivated witch hunt. They’re accusing him of working with a former Grassley aide, now at the State Department inspector general’s office, to dig up dirt on the campaign — an accusation the State IG employee and Grassley both deny and pushed back on as recently as Friday.

"Why are nonpartisan public service positions being used as political pawns, especially if they are being blocked just because Sen. Grassley doesn't want Hillary Clinton to be the next president of the United States?" Senate Minority Leader Reid (D-Nev.) said on the Senate floor on Nov. 9. "How much money will Republicans in Congress waste to try and bring down Hillary Clinton?”

Grassley has pushed back, arguing that his “belief in and exercise of the oversight role by Congress is long-standing and nonpartisan.”

“I went after the Reagan Defense Department for wasteful spending … [and] held up Department of Justice nominees during the Bush administration to get my oversight letters answered, just as I am doing now with the Department of State. And I voted in support of giving the Judiciary Committee the authority to issue subpoenas regarding its inquiry into the firing of U.S. attorneys during the Bush administration,” Grassley said on the Senate floor. “This investigation involves many things, but it does not involve politics.”

Democrats on his committee are also pressuring Grassley, arguing that the Abedin investigation isn't in his jurisdiction and that he initially failed to consult them as he proceeded.

"Many have questioned how the Senate Judiciary Committee has any jurisdiction over employment agreements at the State Department," said Jessica Brady, spokeswoman for Democrats on the Judiciary panel.

On the email issue, Grassley’s panel and Homeland Security Chairman Ron Johnson (R-Wis.) have sought to speak with Bryan Pagliano, Clinton’s personal IT staffer at State, who has invoked his Fifth Amendment rights.

After Pagliano refused to answer questions from congressional investigators, Grassley and Johnson asked State for Pagliano's emails in the hopes of learning more about his maintenance of the Clinton server — messages they still haven’t received in full. They’ve also sought unsuccessfully to speak with Pagliano’s supervisors.

State said one interview has taken place and others have been "scheduled for weeks."

The department, Grassley said on the Senate floor, also won’t say whether Clinton’s private server was approved before it was set up. And State has failed to provide emails between State personnel regarding the server that “we have strong reason to believe exist,” the Judiciary chairman said.

The letter to Samuelson represents the first time Grassley has officially contacted her. Grassley wants to know whether she had the security clearance need to handle Clinton’s emails — hundreds of which have been classified recently — and how she determined which messages were work-related.

“It is imperative to understand your background in determining what is and what is not a federal record, since you apparently played a major role in assisting Secretary Clinton in making a decision as to which emails to delete,” Grassley wrote.

Requests for comment from representatives for Samuelson and the Clinton campaign were not returned.

Samuelson’s name first came up during Clinton confidante Cheryl Mills' closed-door testimony before the House Benghazi Committee in September. Samuelson worked on Clinton's 2008 presidential campaign and then joined her at State as a senior adviser. Mills later tapped Samuelson to help her and Clinton's other lawyer, David Kendall, to screen Clinton’s emails as they determined which ones would be provided to State and made publicly available.

Samuelson was assigned to be the first person to sort out which emails would be turned over, and, according to a source close to her, alerted individuals mentioned in the missives that their private communications would be made public.

Earlier this year Samuelson moved from Washington to New York, where Clinton's campaign is headquartered, with plans to undertake the low-profile but essential task of vetting senior campaign hires. But people who know her say she never started work on the campaign, though she was among the staffers who accompanied Clinton to her Benghazi hearing.

"She moved to Brooklyn to work on the campaign, but then things got really complicated," said a friend of Samuelson who requested anonymity, alluding to Samuelson's previous task of sorting Clinton's personal and work emails and the controversy that Clinton's private server has since become.

National Archives rules require all work messages to be turned over to the government, even if only a sentence of an entire email that’s personal in nature relates to official duties. Clinton and her team said they erred on the side of turning over more emails than she probably was required to, but they haven't answered specific questions about the process they used.

On the Abedin matter, Grassley began asking questions in 2013. News reports then revealed that at the same time she was employed at State, Abedin was being paid by Teneo, a corporate consulting firm that has used its political network to connect executives with influential people in Washington.

Grassley believes Abedin may have had a conflict of interest, though her lawyer and the Clinton campaign have said she had approval for the job and did nothing wrong. Emails that surfaced in September showed Teneo CEO Doug Band, a former longtime Bill Clinton staffer, asking Abedin for help getting a client and Clinton Foundation donor appointed to a White House panel.

Grassley has asked State for Abedin’s work emails and documents related to her work for Teneo. He slapped a hold on about 22 State nominees in early fall to increase pressure on State to cooperate.

Recently, Teneo declined Grassley's request for more documents pertaining to Abedin, saying Washington issues constitute an "insignificant" portion of what it does.

Last week, Grassley dropped his hold on 20 of the nominees, who were appointed to Foreign Service positions. But in addition to blocking Shannon, he continued to hold up nominees for two other senior jobs: Brian James Egan as legal adviser and David Malcolm Robinson to be assistant secretary for conflict and stabilization operations and coordinator for reconstruction and stabilization.