President Donald Trump finally jettisoned National Security Adviser H.R. McMaster on Thursday afternoon. His replacement is John Bolton, the former ambassador to the United Nations in the Bush administration — and one of the most radically hawkish voices in American foreign policy.

Bolton has said the United States should declare war on both North Korea and Iran. He was credibly accused of manipulating US intelligence on weapons of mass destruction prior to the Iraq War and of abusive treatment of his subordinates. He once “joked” about knocking 10 stories off the UN building in New York. That means his new appointment to be the most important national security official in the White House has significant — and frightening — implications for Trump’s approach to the world.

Bolton’s new job was announced on Thursday evening, when the president tweeted that McMaster planned to resign and Bolton would replace him. “I am pleased to announce that, effective 4/9/18, [John Bolton] will be my new National Security Advisor,” Trump wrote.

Bolton had been rumored to be the frontrunner for the job for months, but that doesn’t make the pick any less jarring. His track record in government, connections to anti-Muslim groups, and stated views in op-eds and public speeches all suggest that he will push Trump to take extremely dangerous positions on issues like North Korea, Iran, and ISIS.

“I operate on the assumption that John Bolton should be kept as far away from the levers of foreign policy as possible,” says Christopher Preble, the vice president for defense and foreign policy studies at the libertarian Cato Institute. “I think I would rest easy if he was dog catcher in Stone Mountain, Georgia. But maybe not.”

Bolton’s elevation illustrates the degree to whichTrump is influenced by the conservative infotainment sphere, most notably Fox News — where Bolton has long been an on-air fixture. He was, prior to this appointment, a marginal figure in Washington foreign policy circles since his departure from the Bush administration. But he got himself one of the top jobs in the country because of his savvy work in the world of conservative media and advocacy groups.

As a result, American foreign policy may be soon be shaped by someone who seems to truly believe that war is the answer to the world’s most pressing problems.

John Bolton’s early career shows why he’s a dangerous choice for national security adviser

Bolton is, somewhat ironically, a quintessential creature of the Washington swamp.

After graduating Yale Law School in 1974, where he had become friends with future Supreme Court Justice Clarence Thomas, he went into private practice in Washington. He made a name for himself working in conservative politics, becoming vice president of the right-wing American Enterprise Institute and serving in midlevel roles in the Reagan and George H.W. Bush administrations.

But it wasn’t until the George W. Bush administration that Bolton rose to greater prominence. In May 2001, Bush appointed him to be undersecretary of state for arms control, basically the top diplomat focusing on weapons of mass destruction. This position became fairly important in the runup to the Iraq War, as the Bush administration’s case against Saddam Hussein focused on his alleged nuclear, chemical, and biological weapons.

Bolton took the hardest of possible lines. He forcefully argued that Iraq had WMDs — “we are confident that Saddam Hussein has hidden weapons of mass destruction,” as he put in one 2002 speech. After Bush’s 2002 State of the Union speech connecting North Korea, Iraq, and Iran as an “axis of evil,” Bolton insisted that this wasn’t just rhetoric — that there was ‘’a hard connection between these regimes — an ‘axis’ along which flow dangerous weapons and dangerous technology.’’

He was involved in shaping US intelligence in the runup to the war — and not in a good way. In 2002, Bolton’s staff prepared a speech alleging that Cuba had an active biological weapons program. This wasn’t true, and the State Department’s lead bioweapons analyst at the time would not sign off on the claim. Per the analyst’s sworn testimony to Congress, Bolton then called the analyst into his office, screamed at him, and then sent for his boss. In this conversation, per the Washington Post’s David Ignatius, he derisively referred to the analyst as a “munchkin” and attempted to get him transferred to a different department.

This was cruel and unprofessional, but also dangerous. Carl Ford, then the assistant secretary of state for intelligence and research, testified that Bolton’s assault on the analyst had a “chilling effect” throughout the department, freezing out dissent on proliferation issues beyond Cuba. John Prados, a fellow at George Washington University’s National Security Archives, came to an even broader conclusion in a study of declassified Bush administration documents: Bolton bears a significant amount of blame for the politicized intelligence used to justify the decision to attack Iraq.

“Although Bolton’s actions did not concern Iraq directly, they came to a high point during the summer of 2002 — the exact moment when Iraq intelligence issues were on the front burner — and they aimed at offices which played a central role in producing Iraq intelligence,” Prados writes. “Analysts working on Iraq intelligence could not be blamed for concluding that their own careers might be in jeopardy if they supplied answers other than what the Bush administration wanted to hear.”

None of this got Bolton fired. In fact, it got him promoted: In March 2005, President Bush nominated him to be US ambassador to the UN, one of the most important diplomatic positions in the entire government.

Bolton’s Senate confirmation hearing turned into a vicious fight, largely over his role in shaping the faulty prewar intelligence about Iraq. But his management style, as exemplified by the munchkin incident, also became a huge issue. When Ford was called to testify before the Senate Foreign Relations Committee, he bluntly said Bolton’s personality should disqualify him from holding high office. Ford called him a “bully” who “kisses up and punches down,” among other things.

“I’m as conservative as John Bolton is,” Ford told the committee. “But the fact is that the collateral damage and the personal hurt that he causes is not worth the price that had to be paid.”

Multiple people who had worked with Bolton came out of the woodwork to speak to these issues. Perhaps the most harrowing such account came in an open letter written by a former federal contractor named Melody Townsel, recalling a time that she raised issues surrounding the use of funds in a contract Bolton was working on. He didn’t take it well:

Mr. Bolton proceeded to chase me through the halls of a Russian hotel — throwing things at me, shoving threatening letters under my door and, generally, behaving like a madman. For nearly two weeks, while I awaited fresh direction from my company and from US AID, John Bolton hounded me in such an appalling way that I eventually retreated to my hotel room and stayed there. Mr. Bolton, of course, then routinely visited me there to pound on the door and shout threats.

All in all, according to then-Sen. Joe Biden, the ranking Democrat on the Senate Foreign Relations Committee at the time, testimony from at least five people confirmed multiple instances of Bolton behaving abusively toward subordinates and retaliating against intelligence professionals who challenged his policy positions. For these reasons, Bolton could not be confirmed by the Senate — which was, at the time, controlled by Republicans.

Bolton’s Iraq-era activities are extraordinarily relevant for understanding what he’ll push for as Trump’s national security adviser (a position that doesn’t require Senate confirmation).

Technically, his primary job will be running the National Security Council, which exists to coordinate and synthesize the sometimes conflicting policy proposals that emerge from the Pentagon, State Department, and other agencies. He will present the president with strategic assessments of high-level officials like the secretaries of defense and state, offer his own thinking, and then communicate Trump’s ultimate decision to the agencies and work to ensure it’s implemented.

Put another way, his job is to manage the information that comes to the president and then present a clear-eyed and accurate assessment of what’s happening and how to respond to it. Yet Bolton’s history suggests a long and storied history of cherry-picking intelligence to support his preferred hawkish policies.

“Bolton is so much of an ideologue,” says Mieke Eoyang, vice president for foreign policy at the center-left think Third Way, “that I don’t think he would accurately portray consequences [of policy options] to the president.”

His reported history of berating and undermining anyone who attempted to challenge him is likely to further stifle dissent. He’ll have more power over the White House national security staff as national security adviser than anyone other than the president, giving him unprecedented ability to act as a “bully,” in Ford’s words.

It’s very plausible that Bolton will accelerate the brain drain from the federal government that already seems to be taking shape — not just in the White House but across the various departments that make foreign policy.

“Bolton hates the State Department. He portrays US diplomats as closet Democrats and appeasers,” Richard Gowan, a professor at Columbia University who has studied Bolton’s career, recalls. “As NSA, he would almost certainly encourage the hollowing out of State Trump and [former Secretary of State Rex] Tillerson have begun.”

John Bolton represents the Fox News-ification of foreign policy

Ultimately, Bolton did get the UN ambassador position — though without the Senate’s permission. In August 2005, President Bush appointed him to the post while the Senate was out of session (a so-called “recess appointment”).

Bolton’s year and a half at the UN was characterized by showy condemnations of the organization, which infuriated American allies, but he had little influence on the UN or the overall arc of Bush’s second-term foreign policy.

“Bolton raised hell at the UN, but his actual power was quite limited,” Gowan recalls. “Condi Rice and the mainstream conservatives in the second Bush administration often ignored him. He is quite open about this in his memoirs from that period, which are fun.”

In December 2006, Bolton called it quits, returning to civilian life. He became a fixture on Fox News and conservative talk radio, where his confirmation fight and anti-UN rhetoric was hailed as a sign of his willingness to speak truth to power. He was so prominent in these spheres, mostly through his contract as a Fox contributor, that he considered running for president in both 2012 and 2016.

Bolton was particularly popular among a small but influential group of hardline anti-Islam activists, the “counter-jihad” movement, who believed the US government was being infiltrated by Islamists and that Islamic law was quietly taking over the US legal system.

Bolton wrote the foreword to a book by two of the most prominent counter-jihadists, Pamela Geller and Robert Spencer, in 2010. In 2016, Bolton spoke at a conference held by the American Freedom Alliance, considered a “hate group” by the Southern Poverty Law Center, titled “Can Islam and the West Coexist?” His speech contained a “joke” whose punchline was that President Obama was a Muslim.

In his many media appearances and public appearances, Bolton never wavered from the kind of hawkish policy views he established during the Bush administration. In a 2015 New York Times op-ed, Bolton advocated for a US and/or Israeli airstrike on Iranian nuclear facilities. “Time is terribly short, but a strike can still succeed,” he wrote. “Such action should be combined with vigorous American support for Iran’s opposition, aimed at regime change in Tehran.”

Since Trump took office, Bolton has put the media savvy and experience with the conservative movement he’s developed to good use — using various levers to influence the president. In just the first months of 2018, Bolton has appeared on Fox News roughly 20 times. He has used those appearances to sell his policy preferences, warning against diplomacy with North Korea and encouraging Jordan to annex the West Bank (much of which remains under Israeli occupation despite the fact that the vast majority of its citizens are Palestinian).

During the early Trump administration, then-White House senior strategist Steve Bannon approached Bolton as part of a plan to get around Cabinet members, like Secretary of Defense Jim Mattis, who opposed withdrawal from the Iran nuclear deal. Bolton drafted a five-page memo detailing his proposal for tearing up the deal, which he then published in National Review after Bannon departed the White House.

And in February 2018, he published an op-ed in the Wall Street Journal arguing that the US needed to solve the nuclear standoff with North Korea by force.

“Pre-emption opponents argue that action is not justified because Pyongyang does not constitute an ‘imminent threat.’ They are wrong,” Bolton wrote. “It is perfectly legitimate for the United States to respond to the current ‘necessity’ posed by North Korea’s nuclear weapons by striking first.”

Bolton’s record in the Bush administration and general hawkishness made him a marginal figure in Washington foreign policy conversations. So after leaving, he cannily aligned himself with Fox News and other influential groups on the right, like the counter-jihadists, who saw him as an experienced and credible commentator. This led not only to television news and book contracts but to platforms through which he could potentially influence actual Republican elected officials.

This reached a kind of apogee with President Trump. Trump sees the world through a televisual lens; he seems to get more information from Fox News than from his daily intelligence briefings. The president values the advice of people he sees on the TV and other friendly media outlets. Bolton is not seen as a relic of the hated Bush administration; he’s seen as an authoritative and expert Fox voice. According to Bolton’s National Review piece, Trump once told him to “come in and see me any time” in the White House.

Now, of course, Bolton will have a permanent home in the White House. The reason he didn’t have an administration sooner, according to some press accounts, is aesthetic. In December 2016, the Washington Post reported that Bolton was eliminated from the running for secretary of state because Trump — I swear I’m not making this up — didn’t like his mustache.

“Donald was not going to like that mustache,” one Trump associate told the Post. “I can’t think of anyone that’s really close to Donald that has a beard that he likes.”

Perhaps because of the mustache, Trump hadn’t taken Bolton’s policy advice to heart in his first year in office. There’s no war with North Korea, and the Iran deal remains (largely) intact.

But now Bolton is national security adviser, with direct access to the president and tremendous influence over a vast and powerful national security bureaucracy. And many foreign policy experts are deeply concerned about what that means.

“The United States has not hit rock bottom in our international relations,” says Eoyang. “[With Bolton], we could go lower.”