Steve Bannon, the chief strategist in President Trump’s White House, is a bare-knuckled political brawler who has told the news media to “keep its mouth shut” and helped craft a controversial new executive order on immigration without talking to the Cabinet secretaries charged with carrying it out.

All of that makes his new appointment to a full seat on the Principals Committee of the National Security Council all the more jarring. No White House political adviser has ever previously served on the NSC, which is charged with giving Trump unvarnished advice about literal life-and-death national security issues.

It’s difficult to overstate the significance of Bannon’s appointment — or the dangers. Bannon made his name at Breitbart News, a far-right and Islamophobic news site that once used a photo of an old Adidas shirt as evidence that Islamist terrorists were sneaking across the Mexican border (Breitbart claimed it was a Muslim prayer rug). He has also had a long career directing pseudo-documentaries with titles like District of Corruption and In the Face of Evil: Reagan’s War in Word and Deed. Now he has a seat at the table where questions of war and peace are debated and decided.

Bannon’s elevation would be surprising in and of itself. But what makes it truly alarming — to critics from both parties — is that it’s taking place alongside a separate provision downgrading the status of the chairman of the Joint Chiefs of Staff and the director of national intelligence. Under all previous presidents, both officeholders attended all NSC meetings. In the Trump administration, they’ll only come when “issues pertaining to their responsibilities and expertise are to be discussed.”

This means that a political operative with zero national security or foreign policy experience will now have the same status as the heads of the Pentagon and State Department — and will in some ways outrank the nation’s top military officer and the head of the entire intelligence community.

“Republicans and Democrats have always understood that this was not a place for politics,” said Ryan Crocker, who frequently briefed the NSC during his time as ambassador to Iraq and then to Afghanistan. “If the chairman of the Joint Chiefs of Staff and the director of national intelligence aren’t involved, who’s providing the military perspective and the intelligence background? How can hard decisions be made if some of the important voices aren’t even in the room?”

Trump’s executive order temporarily banning immigration from seven majority-Muslim nations is rightly attracting enormous amounts of political, legal, and media scrutiny. On the surface, White House personnel moves don’t seem even remotely as important. This one, though, is getting more public notice than you’d expect, like in this widely shared photo from an anti-ban protest at Los Angeles International airport:

That’s because this is no ordinary White House, and these are no ordinary bureaucratic changes. They will — in a very tangible way — help shape the future of the entire Trump administration and the future of US foreign policy.

The National Security Council isn’t a place for politics — but Trump may make it one

The NSC was created in 1947 so the nation’s military, diplomatic, and intelligence officials would have a place to analyze specific short- and long-term aspects of US foreign policy and national security. It has a staff of nearly 200 people, mostly career civil servants and military officers detailed from places like the CIA. Those staffers are overseen by a small number of political appointees from the new administration.

The principals committee itself, which Bannon is now joining, is a very different beast. That’s a far more exclusive place where the most powerful people in the US government — like the secretary of state and the secretary of defense — gather to debate and discuss specific questions about counterterrorism, military operations, and other vital issues before kicking them up to the president for a final decision on how to proceed. (They are chaired by the national security adviser; the president himself doesn’t attend them.)

This is Washington, so political considerations have always impacted the NSC’s work, but presidents of both parties have worked hard to draw a line between domestic political considerations and the life-and-death questions faced by the NSC.

President George W. Bush’s top political aide Karl Rove once attended an NSC meeting, and the president was so livid that he told Rove to never do so again. Former Bush Chief of Staff Josh Bolten, who described the exchange at a conference about the NSC last fall, said Bush believed Rove’s mere presence sent the wrong message.

“The president also knew that the signal he wanted to send to the rest of his administration, the signal he wanted to send to the public, and the signal he especially wanted to send to the military is that the decisions I’m making that involve life and death for the people in uniform will not be tainted by any political decisions,” Bolten said.

According to the New York Times, President Obama allowed top political strategist David Axelrod to sit in on some NSC meetings, but gave him no formal role and made no effort to downgrade the relative status of the chairman of the Joint Chiefs or the director of national intelligence.

Bannon, by contrast, will be a permanent part of the NSC for the duration of the Trump presidency. That means he’ll have a voice in discussions over complex issues like how to handle the war in Syria, whether to ramp up US counterterrorism efforts in Yemen — where a member of the Navy’s elite SEAL Team Six was killed last weekend — or whether to use force against Iran.

Bannon, a political operative with no national security experience, will now have the same status as the heads of the Pentagon and State Department

Bannon’s mere presence during those discussions could prove problematic because the political and national security imperatives facing the NSC are often at odds with each other.

In 2007, the Bush administration began debating whether to “surge” tens of thousands of American reinforcements to Iraq, where the worsening civil war had triggered unprecedented levels of carnage. Bush’s military advisers believed sending more troops was the only way to turn around a failing war, but the notion of doubling down on what many Americans saw as a lost cause had little public support.

Crocker, who participated in the NSC deliberations from his embassy in Baghdad, told me that Bush might not have made the decision to order the reinforcements if a prominent political adviser like Bannon had been sitting at the table and thinking solely in terms of domestic political considerations.

“If we had that model during Iraq, it would have been a very different outcome, because politically the surge was so unpopular at home,” Crocker told me.

Charles Kupchan, who just stepped down as the NSC’s senior director for European affairs under Obama, said Bannon’s mere presence at the table could hamper the talks because staffers wouldn’t feel free to openly discuss topics that might be at odds with current Trump administration thinking on a given issue.

“His presence could stymie debate because Cabinet members may be less willing to speak up knowing that the president’s consigliere is in the room,” said Kupchan, now a professor at Georgetown University and senior fellow at the Council on Foreign Relations. “We also need to be honest: This is not just about any political adviser being added to the NSC. It’s about this specific political adviser, with the temperament he has and the views he espouses. They don’t make him seem particularly well-suited to this kind of job.”

Stephen Biddle, a professor of political science and international relations at George Washington University, said it’s legitimate for a president to want to make sure he has political support for his foreign and national security policies. The problem, he told me, comes from “subordinating foreign policy as an instrument to serve domestic partisan advantage.”

Biddle also noted that elevating Bannon while demoting the chairman of the Joint Chiefs and the director of national intelligence removes people with deep expertise on the complicated issues the NSC has to confront while replacing them with a man who knows politics, not national security.

“For an administration whose early behavior has been marked by apparent great interest in domestic political messaging and limited interest in the details of policy content, this is not a promising sign,” Biddle said.

Indeed, the chairman of the Joint Chiefs of Staff, Gen. Joseph Dunford, actually released a highly unusual statement effectively insisting that he will still be an important player in the Trump White House and that he will “fully participate” in White House debates on national security.

The NSC was in bad shape before Bannon got there. It’s going to get worse.

Bannon’s promotion to the NSC may be even more problematic because of the man nominally running the show: National Security Adviser Michael Flynn, a retired Army general.

When he assumes his new role, Bannon will be joining an NSC suffering from what close observers describe as low morale, staffing woes (the administration has yet to fill dozens of key posts), and lingering questions about Flynn’s competence and temperament.

The Obama administration fired Flynn from his last post in government, as the Pentagon’s intelligence chief. As my colleague Zack Beauchamp and I have written, Flynn “swims in the same swamp of hyperpartisan, frequently fabricated, and disturbingly anti-Muslim rhetoric” as Bannon. Flynn’s tweets include a video that claims “Islam ... wants 80 percent of humanity enslaved or exterminated,” which he captioned “Fear of Muslims is RATIONAL.”

Guessing how long Flynn — who has been clashing with Defense Secretary James Mattis and other top Trump officials in recent weeks — will keep his job has become a popular Washington parlor game (my money is on him being out by spring).

But Flynn’s departure may come even sooner than that. According to the New York Times, Trump himself has rapidly begun to sour on Flynn “because of his sometimes overbearing demeanor” and for “presiding over a chaotic and opaque NSC transition process.” And that’s not all:

Mr. Flynn’s reputation has raised questions among some in the cabinet. Two weeks ago, both men held a meeting with Rex W. Tillerson, Mr. Trump’s pick to run the State Department, Mr. Mattis and Mike Pompeo, now the C.I.A. director, to discuss coordination — Mr. Flynn was invited but did not attend. Part of the meeting was devoted to discussing concerns about Mr. Flynn, according to an official with knowledge of it.

If Flynn leaves or is pushed out, Bannon will be the NSC member with the closest and longest-standing ties to the president. He took over Trump’s presidential campaign at its lowest moment and helped right the ship, in part by encouraging Trump to adopt an even more nationalist message rather than to move to a more conventional one.

Since Trump’s surprise win, Bannon has become one of the most powerful people in the new administration, playing a key role in picking individual Cabinet appointees and helping to personally craft the new president’s enormously controversial executive orders. Trump, according to Politico, sees Bannon “as a peer rather than as an employee” who shares his disdain for the Washington establishment.

With his ascent to the NSC, Bannon’s influence over Washington’s most powerful national security organization will almost certainly grow, not shrink, in the months and years ahead. Steve Bannon’s tenure at the NSC has just started. It won’t be ending anytime soon.