Donald Trump seems to have little use for intelligence. He openly disdains the CIA’s conclusions about Russian hacking, claiming that no one really knows who stole emails from the Democratic National Committee. His transition team has mocked the intelligence community for getting it wrong on Iraq’s weapons of mass destruction. And he is uninterested in receiving the President’s Daily Brief, which has been part of the president’s morning routine for decades. Instead, he wants briefers to stay in touch with his advisors. They’ll let him know if anything important happens.

Who are those advisors? One key figure is retired Lt. Gen. Michael Flynn, Trump’s pick for national security advisor. Flynn has a checkered history with intelligence. As a military commander he earned high praise for using tactical intelligence to undermine al-Qaeda’s network in Iraq. But as director of the Defense Intelligence Agency (DIA), his reputation was toxic. The New York Times reports that at an early meeting with DIA officials, “Mr. Flynn said that the first thing everyone needed to know was that he was always right. His staff would know they were right, he said, when their views melded to his.”

His attitude towards the CIA was also combative. While in uniform in Afghanistan, he co-authored a report concluding that the intelligence community was only “marginally relevant” to U.S. strategy. Since retiring from the military, his comments have become more hostile, including an interview last year in which Flynn accused the agency of being a political tool for the Obama administration.

Trump’s faith in Flynn implies a lack of belief in the intelligence community, and his reputation for power plays suggests he will try to bend it to his will, especially after the CIA reportedly claimed that the Kremlin sought to place him in power. Politicizing intelligence, however, will have terrible consequences. In the short-term it is likely to skew CIA assessments. Difficult questions that require careful and nuanced answers will increasingly reflect Trump’s blunt views.

In the medium-term, intelligence assessments will become myopic and inflexible. Having experienced pressure from above, officials will want to avoid revisiting earlier findings in ways that challenge the administration’s beliefs. Politicized intelligence agencies tend to double down on their conclusions, even if new information emerges that should force a reassessment.

But the greatest risk is long-term. Episodes of politicization have effects that linger for years or decades. Turmoil between policymakers and intelligence agencies reinforces negative stereotypes: As relations deteriorate, policymakers see intelligence officials as bureaucratic obstacles, and intelligence officials see policymakers as meddling bullies. It takes a long time to rehabilitate intelligence-policy relations after mutual mistrust and hostility sets in.

The Iraq War – which Trump’s transition team used to attack the CIA’s credibility – is a cautionary tale. Contrary to Trump’s statements, the notorious Iraq estimates were as much a result of policy pressure from the George W. Bush administration as they were from analytical errors. The hothouse environment before the war transformed beliefs about Iraq – which were wrong but measured – into a consensus that went far beyond previous estimates. Worst-case scenarios became mainstream positions.

Having gone public, intelligence leaders were reluctant to revisit their findings, even though new information from U.N. weapons inspectors threw doubt on the intelligence community’s conclusions about Iraq’s WMD. Doing so would have been an embarrassing and dangerous admission of earlier errors.

After the invasion revealed no such weapons, Bush administration officials publicly blamed the intelligence community for delivering faulty conclusions. Intelligence officials responded in kind. Years passed before relations recovered.

One lesson of the Iraq War is that intelligence should be handled with care. Answers to the most important questions about national security are rarely straightforward. At its best, intelligence helps policymakers by reducing uncertainty, not by offering point predictions about future events. Narrowing the bounds of uncertainty helps identify the range of plausible policy options.

Politicizing intelligence makes this impossible. By forcing intelligence to toe the policy line, it creates and reinforces a policy echo chamber. And by appointing hostile figures to lead intelligence agencies, it risks driving away experienced analysts who are critical in the best sense of the term. The upshot is that politicized intelligence is not just wrong, but aggressively and self-confidently wrong.

None of this needs to happen. The campaign is over. Trump does not need to beat up intelligence professionals to score political points. On the other hand, he may find it useful for understanding international responses to his provocative plans, and for dealing with crises and unexpected events. As the president-elect wraps up his victory tour and settles into the work of governing, he should ratchet down his rhetoric about the intelligence community. He should also look for a director of national intelligence who is widely respected for his integrity and independence.

Intelligence leaders are not passive actors either. While they must respond to legitimate requests from the White House, they should not pander to the administration in hopes of currying favor later. This type of “soft politicization” usually backfires. They must also resist the urge to enter into public debates. The more that intelligence agencies enter the fray, the more they become just another bureaucratic player, subject to the normal slings and arrows of Washington politics. CIA director John Brennan’s public support of the Iran nuclear deal, for instance, has not helped the agency’s claim to be impartial and objective.

Trump’s pick for director of the agency, Mike Pompeo, has been noticeably silent since his nomination. His discretion will be important if the CIA hopes to play a useful role in the policy process. The alternative is to continue down the road to politicization, which will do grave damage to intelligence and policy alike.

Joshua Rovner is the author of Fixing the Facts: National Security and the Politics of Intelligence (Cornell University Press, 2011).