WASHINGTON — For what is supposed to be perhaps the most nonpartisan job in Washington — the director of national intelligence — President Trump has selected one of the fiercest political warriors in the capital.
Mr. Trump’s choice, Representative John Ratcliffe of Texas, has established himself during his nearly five years in Congress as a tough partisan and as one of Mr. Trump’s most effective defenders. A relentless critic of the Russia investigation, Mr. Ratcliffe has shared some of Mr. Trump’s views and earned praise from critics of the so-called deep state of government bureaucrats.
Democrats have said he is unqualified and too overtly political, and even some Republicans privately said they thought Mr. Ratcliffe was the wrong choice, according to people familiar with their thinking. Senator Richard M. Burr, Republican of North Carolina and the Senate Intelligence Committee chairman, waited nearly a day to publicly congratulate Mr. Ratcliffe, a subtle sign of discontent with the shake-up. But Republicans on the committee, which will vote on whether to send the nomination to the full Senate, are highly unlikely to buck Mr. Trump.
The political winds from the Trump White House have buffeted the intelligence agencies, and Dan Coats, the current director of national intelligence, has worked to insulate them. If Mr. Ratcliffe is confirmed for the post, some current and former American officials believe that other top intelligence officials like the C.I.A. director, Gina Haspel, and the F.B.I. director, Christopher A. Wray, could lose their shield against White House interference and partisan criticism.
The intelligence chief “is not a political job,” said Senator Angus King, a Maine independent on the Intelligence Committee who caucuses with the Democrats.
“This isn’t like secretary of state or secretary of defense; this is a fact job,” he said. “Because it is human nature to want to tell the boss what he or she wants to hear, you have to have somebody with real backbone.”
Mr. Ratcliffe’s Republican defenders insist he is fair. His political bite is largely virtue of circumstance, they said, adding that he harbors greater respect for the law enforcement and intelligence communities than many House Republicans in his circle.
In private, his allies said, he is inclined to give national security officials the benefit of the doubt and has defended — sometimes against his political allies — the need for law enforcement and intelligence agencies to have access to tools like domestic surveillance. And despite criticisms of the Russia investigation, they point out, he did not join calls for Robert S. Mueller III’s removal as special counsel or question evidence of Russian interference.
Democrats’ criticism of Mr. Ratcliffe is “more reflective of the political environment we are in than John Ratcliffe,” said Trey Gowdy, the former congressman from South Carolina who like Mr. Ratcliffe is a former federal prosecutor. The Justice Department has placed the F.B.I. and the C.I.A. under scrutiny over the origins of the Russia inquiry, and Mr. Trump has told intelligence leaders to “go back to school” for their assessments of North Korea’s nuclear program.
“Look, it’s been a rough environment — the Mueller probe, the investigation into D.O.J. and F.B.I.,” Mr. Gowdy said. “But you go pull the transcripts and you find me the question that even a Democrat lawyer would tell you was unfair, ill founded, not factually predicated.”
Mr. Ratcliffe pledged in a statement on Sunday to “work on behalf of all the public servants who are tirelessly devoted to defending the security and safety of the United States.”
If Mr. Ratcliffe is confirmed, the appointment would deprive the president of one of his ablest allies in the House. Mr. Ratcliffe has played an important role in building the case that the F.B.I. harassed Mr. Trump. Republicans consider Mr. Ratcliffe so important to Mr. Trump’s defense on Capitol Hill that his appointment would have been less likely if they still feared that Democrats would advance an impeachment case against Mr. Trump, said one lawmaker familiar with the president’s thinking.
Mr. Trump, of course, has named other partisans to top intelligence jobs. Secretary of State Mike Pompeo, Mr. Trump’s first C.I.A. director, had a reputation as a strong skeptic of the Iran nuclear deal and a critic of the Obama administration’s handling of the Benghazi attacks.
But Mr. Pompeo appointed Ms. Haspel, an agency veteran, as his deputy and quickly came to rely on her expertise, signaling to the C.I.A. rank and file that he valued intelligence professionals.
Mr. Ratcliffe, however, has indicated that he intends to clean house, according to people familiar with his plans. The fate of Mr. Coats’s deputy, Sue Gordon, who runs the office’s day-to-day operations, is unclear. The White House did not immediately announce that she would serve as the acting director when Mr. Coats departs on Aug. 15, as is typical.
Republicans on the House Intelligence Committee have long been pushing for an overhaul of the Office of the Director of National Intelligence, eliminating jobs, slimming the agency and changing how it operates. Mr. Ratcliffe, according to American officials, is likely to try to push through some of those changes if confirmed.
But Mr. Gowdy expressed skepticism that Mr. Ratcliffe would be focused on shaking up the office and said he believed his attention would be on counterterrorism and cyberoperations. “People are most upset with John because he is good at what he does,” Mr. Gowdy said. “He is also going to be good at what he is fixing to do, and that is intelligence, not politics.”
The White House has considered Mr. Ratcliffe for at least one law enforcement position in recent months, and he won over Mr. Trump in a meeting in recent weeks. He appeared to have sealed the intelligence nomination by executing one of the most effective Republican attacks on Mr. Mueller during his closely watched House testimony last week.
In addition to the reservations over Mr. Ratcliffe’s partisanship, some former intelligence officials have said they do not think he has the necessary background for the job.
The 2004 law establishing the post set the criteria for the director as having “extensive national security expertise.” Mr. Ratcliffe is a former United States attorney and mayor of Heath, Tex., a town of nearly 9,000 outside Dallas. He joined the House Intelligence Committee this year.
Though directors of national intelligence do not have to have served as intelligence officers — Mr. Coats did not — they should be deeply immersed in national security and the uses of intelligence, said Mark M. Lowenthal, a former senior C.I.A. official.
“This is not a great position for on-the-job training,” Mr. Lowenthal said. “There is a very steep learning curve.” A legal challenge to Mr. Ratcliffe’s nomination is doubtful. But if some Republican senators have private doubts over Mr. Ratcliffe, they could use the legal requirement to slow the nomination or even oppose it.
While Republicans have been loath to block Mr. Trump’s appointments, they have slow-rolled some nominations, like former Acting Defense Secretary Patrick M. Shanahan’s nod to take the job permanently. After a drawn-out review of Mr. Shanahan’s background and qualifications, he ultimately withdrew.
Mr. Trump’s announcement provoked fears among former law enforcement officials that Mr. Ratcliffe would continue his assault on the F.B.I. He is central to a group of staunchly pro-Trump conservatives in the House who have aggressively dogged the F.B.I. and the intelligence agencies over their handling of the Russia investigation and the Hillary Clinton email inquiry, two of the most politically charged investigations in the bureau’s history.
“The D.N.I. must bring leadership to the intelligence community that fosters the independence and candor of the intelligence analysis presented to policymakers,” said David Laufman, a former top Justice Department official involved in both investigations.
“Mr. Ratcliffe’s partisan political behavior on behalf of the president, including attacks on the special counsel’s investigation, raises serious questions about whether he possesses the requisite qualities to fulfill that responsibility.”
Mr. Ratcliffe helped privately depose dozens of executive branch officials summoned to Capitol Hill to talk about the cases, and his questioning of top law enforcement officials, including the former F.B.I. director James B. Comey, proved to be memorable television.
During a September 2016 Judiciary Committee hearing, Mr. Ratcliffe leaned into his experience as a federal prosecutor to accuse Mr. Comey of deciding not to charge Mrs. Clinton before investigators had interviewed her and of failing to pursue evidence that Mr. Ratcliffe said could demonstrate Mrs. Clinton and her aides were obstructing justice.
“Any one of those in that very, very long list to me says obstruction of justice,” Mr. Ratcliffe told the former director. “Collectively, they scream obstruction of justice. And to ignore them really allows not just reasonable prosecutors but reasonable people to believe that maybe the decision on this was made a long time ago not to prosecute Hillary Clinton.”
Mr. Comey denied the allegations and suggested Mr. Ratcliffe was straying from the truth. “We’re in a fact-based world,” Mr. Comey said. “So we make evaluations based on the evidence we are able to gather based on the tools that we have. So it is hard for me to react to these things that you don’t have.”
Mr. Ratcliffe has also attacked the Russia investigation, criticizing the F.B.I. for using political opposition research in obtaining a secret application to wiretap a former Trump campaign adviser. He has expressed doubts about the origins of the investigation and repeatedly fanned conspiratorial flames embraced by right-wing media. He has also become a regular on Fox News, the president’s favorite channel.
“What I do know as a former federal prosecutor is that it does appear that there were crimes committed during the Obama administration,” Mr. Ratcliffe said Sunday on Fox Business Network.
The Justice Department’s inspector general is investigating whether the F.B.I. acted improperly in conducting aspects of the Russia inquiry. The inspector general’s findings are expected in the coming weeks.