Deputy Attorney General Rod J. Rosenstein sent a memo to President Trump which ultimately led to the firing of FBI director James Comey. Here's what you should know about Rosenstein. (Amber Ferguson/The Washington Post)

Senate Democrats pummeled Deputy Attorney General Rod J. Rosenstein on Thursday for his involvement in the firing of FBI Director James B. Comey, warning that his nonpartisan reputation is at risk unless he starts answering questions from Congress.

Senate Minority Leader Charles E. Schumer (D-N.Y.) sent Rosenstein a letter Thursday with detailed questions about his involvement in the ouster of Comey. He warned that Rosenstein’s reputation as an “independent, apolitical actor” is in jeopardy unless he begins sharing details.

“Over the last three decades of your career at the Department of Justice, you have developed a reputation for integrity and impartiality,” Schumer wrote. “That reputation, along with the personal and public commitments you made to me and other Senators that you would be an independent, apolitical actor as Deputy Attorney General, earned you broad bipartisan support in your confirmation vote. And that reputation is now imperiled by your participation in the abrupt dismissal of FBI Director Comey.”

Schumer asked for answers by Monday to the questions, including whether it is true that Comey had asked the Justice Department for more resources for the FBI investigation into Russian meddling in the U.S. elections; whether Rosenstein conveyed that request to the White House; whether he met with President Trump on Monday and whether he knew the subject of that meeting in advance; and details of the memo Rosenstein wrote for Trump to help justify removing Comey.

But if recent history is any guide, Rosenstein is unlikely to provide a line-by-line response, and Democrats would be likely to use his silence as further justification to continue holding up business in the Senate and to put more pressure on congressional Republicans to call for a special prosecutor to investigate Russia’s meddling.

Other senior Democrats stepped up their criticism of Rosenstein on Thursday, suggesting his three-page memo outlining the rationale for firing Comey was an amateur piece of work that lacked the legal foundation that they expected given his long tenure and credentials in the Justice Department.

Sen. Dianne Feinstein (D-Calif.), the ranking Democrat on the Judiciary Committee and a top member of the Intelligence Committee, said she has now read Rosenstein’s memo three times and has remained incredulous that he wrote it as the basis for Comey’s firing. She pointed out portions of the second page of the memo, which used quotes from op-eds by and news clippings about former Justice Department officials critiquing Comey’s actions during the investigation of Hillary Clinton’s email server.

“That surprised me, that a guy as highly prized as Rosenstein, on the basis of legal talent, professionalism in the department, would pull things out of a newspaper and quote them, in terms of somebody else’s opinion of Comey,” Feinstein said.

She said he needed to appear before the committee to explain himself. “The memo was a surprise, and it means to me we really have to have him in and talk to him, because, wow, I mean, I could have written it,” the 83-year-old non-lawyer said, adding that it looked like something news-media types would have cobbled together.

Sen. Patrick J. Leahy (D-Vt.), the former chairman of the Judiciary Committee, said that his reading of the memo showed no mention of dismissing the FBI director and said the best way to clarify the matter was a public hearing.

“You’re always better when you can ask [questions] at a hearing,” Leahy said.

Leahy and Sen. Jeanne Shaheen (D-N.H.), who sit on the Appropriations Committee and oversee funding for the Justice Department, also sent a letter to Rosenstein asking that he specify the circumstances surrounding Comey’s request for more funding for the Russia probe.

“The American people have a right to know, for the sake of our national security and sovereignty, whether and to what extent Russia interfered in the 2016 Presidential election. The Federal Bureau of Investigation (FBI) and the Department of Justice (DOJ) should dedicate the needed personnel and resources to the investigation without hesitation,” Leahy and Shaheen wrote in a letter to the deputy attorney general.

The senators added that they want “the details of any request for increased resources made by the FBI to DOJ” and “how this request was communicated from the FBI to DOJ, and whether similar requests were made to the White House.” They are also curious to learn about “any other constraints that might limit the FBI in conducting a thorough investigation.”

Here’s the full text of Schumer’s letter:

May 10, 2017

The Honorable Rod Rosenstein
Deputy Attorney General
U.S. Department of Justice
950 Pennsylvania Avenue NW
Washington, DC 20530

Dear Mr. Rosenstein,

Over the last three decades of your career at the Department of Justice, you have developed a reputation for integrity and impartiality. That reputation, along with the personal and public commitments you made to me and other Senators that you would be an independent, apolitical actor as Deputy Attorney General, earned you broad bipartisan support in your confirmation vote. And that reputation is now imperiled by your participation in the abrupt dismissal of FBI Director Comey.

Your memorandum to Attorney General Sessions described disagreement with Director Comey’s conduct last summer and fall; it was used as the justification for his dismissal this week. However, there is widely reported skepticism that the reasons laid out in your memo are the real basis for the President’s decision to fire Director Comey. This skepticism, and indeed all of the circumstances surrounding Director Comey’s dismissal just as he was leading an investigation into the Trump administration’s and Trump campaign’s ties with Russia and President Putin’s interference with the 2016 election, have shaken public confidence in the Department, in your leadership, and in the administration of law and justice in our country.

In order to restore the nation’s faith in you personally and in our law enforcement system more broadly, the American people must understand more about your role in the President’s firing of Director Comey. To that end, please answer the following questions by Monday, May 15th.

1. It was publicly reported that Director Comey last week asked you for additional resources for the investigation into the Trump campaign’s connection to Russia. Are these reports accurate?
a. Did Director Comey recently provide you with a briefing on this investigation or any other politically sensitive investigation? Please describe the date and circumstances of any such update.
b. Did you convey any information provided by Director Comey to Attorney General Sessions or anyone in the Executive Office of the President? Please describe the date and circumstances of any such conveyance.

2. It was reported that the President decided over the weekend to fire Director Comey and summoned you and Attorney General Sessions to the White House to discuss the Director on Monday May 8th. Are these reports accurate?
a. Did you meet with the President on Monday, May 8th?
b. Were you aware what would be the topic of the meeting before you arrived?
c. Did you discuss the topic of the meeting with Attorney General Sessions or anyone in the Executive Office of the President before the meeting?
d. Who was present at the meeting?
e. Did the President or anyone else tell you the President had made a decision to fire Director Comey?
f. Did the President or anyone else ask for a justification to fire Director Comey?
g. Did the President or anyone else direct you to write your memo?

3. On Tuesday, May 9th, you sent a memorandum to the Attorney General entitled “Restoring Public Confidence in the FBI.” What were the circumstances that led to the drafting and transmittal of this memo?
a. Who participated in the drafting of the memo, including but not limited to its preparation before it was finalized?
b. Who provided guidance, in any form whatsoever, on the memo’s contents, style, timing or any other element?
c. Who was aware that the memo was being prepared?
d. Who reviewed the memo before it was finalized?
e. Were you aware when you drafted the memo that it would be used to justify the firing of Director Comey?
f. Why does the memo not explicitly call for the Director to be dismissed?
g. Was Attorney General Sessions or anyone in the Executive Office of the President involved, in any capacity whatsoever, in the planning, drafting, consideration, review, or transmittal of the memo?

4. Attorney General Sessions recused himself from any role in the investigation of Russia’s involvement in the 2016 elections and the Trump campaign because of his close relationship with the campaign and his own undisclosed contacts with Russian officials. Yet your memorandum is addressed to him and, according to public reporting, he participated in the decision to fire Director Comey. How do you reconcile Attorney General Sessions’s participation with his ethical obligations under the Department’s recusal guidelines?
a. Did you and Attorney General Sessions ever discuss whether it would be improper for him to be involved in the dismissal of the lead investigator of a politically sensitive investigation from which he was recused?
b. Did you or anyone else in the Justice Department ever advise Attorney General Sessions not to participate in these discussions or the dismissal?
c. Did you seek, or are you aware of anyone else at the Justice Department seeking, advice or counsel about whether it was appropriate for Attorney General Sessions to participate in these discussions or the dismissal?

5. After Director Comey was fired, the White House said that you had initiated the memorandum on your own and that you instigated the decision to remove him. Yet this morning, press reports indicate that you threatened to resign because “the narrative emerging from the White House on Tuesday evening cast [you] as a prime mover of the decision to fire Comey and that the president acted only on [your] recommendation.” Are these reports accurate?
a. Did you object, either to the White House, to Attorney General Sessions, or to anyone else, to the media characterizations of your role in the firing?
b. Did you take any steps to correct any inaccuracies in the public record?
c. Did you discuss the possibility that you might resign from the Department with anyone?

I look forward to your prompt response to my letter. In addition, I hope you will make yourself available to me and all of my colleagues to answer these and other additional questions that will arise.

Sincerely,

Charles E. Schumer