John F. Kelly. (Susan Walsh/Associated Press)

In the U.S. Armed Forces, the Orders to Sentry provide strict protocols governing the posting of military guards. Drill instructors commonly pepper recruits to test their memory of the codes. Yet while assignments of sentries can be vitally important, the assignees are typically of low rank.

Not so in President Trump’s White House, where it takes a general to be a gatekeeper. Or so many in the GOP hope now that retired Gen. John F. Kelly is President Trump’s chief of staff.

Given this administration’s ignominious rate of turnover, though, the question of the moment is how long Kelly will stand guard. Have your own opinion? The reader with the best guesstimate will receive a free “Democracy Dies in Darkness” T-shirt. (Congratulations to last round’s winners: Nabrissa Khan, Hal Kramer, Ruth Malinoff, Susan Petrone, Bob Philpott and Josh Sung.)

Background

Kelly holds the keys to a chaotic kingdom. Recall the scene in “Apocalypse Now,” when Martin Sheen’s character arrives at a manic firefight and asks the gunner, “Who’s the commanding officer here?” To which the soldier replies, “Ain’t you?”

Ironically, the infighting and dysfunction of this administration recall the president’s own inaugural address, when he invoked the specter of “American carnage.” Perhaps Kelly can negotiate the necessary cease-fires. After all, it was President Dwight Eisenhower who borrowed the title for this office from the military when he installed the first top aide to be called chief of staff. (The aide in question, Sherman Adams, was forced to resign in disgrace for receiving an expensive vicuña coat from a favor-seeker.)

The average service in this office, according to Chris Whipple’s book “The Gatekeepers,” is 18 months. Will Kelly surpass that? His body language during Trump’s disastrous press conference Tuesday doesn’t suggest a man happy in the job.

Timothy Naftali, who ran the Richard Nixon Presidential Library and is now a clinical associate professor of public service at New York University’s Robert F. Wagner Graduate School of Public Service, demurs on prognosticating. (He expressed similar reticence when we asked, “Who will be the next Trump staffer to go?”) But Naftali does provide insightful context.

“The scene is set for waves of tension between Gen. Kelly and our impulsive, self-absorbed and misinformed Chief Executive,” he says. “Absent some political earthquake, the length of Kelly’s tenure will depend on the balance he can strike between a patriotic desire to make Trump as fit a commander in chief as possible and the cumulative effects of Trump’s compulsion to go AWOL. And it will be tough to persuade the President that this should not be a family-run business.”

Indeed. When Kelly was sworn in, the first daughter embraced working “alongside” the new chief.

But when asked if all that means that Kelly will depart in fewer than 18 months, Naftali remains guess-shy. “If you look at many of the short-timers,” he says, “they came at the end of administrations. And that has brought down the average.”

Predictions

Bruce Ackerman, Sterling professor of law and political Science at Yale:

Kelly can stay as long as he wants, but I suspect he’ll leave in the fall of 2019, when Trump will need a different Chief of Staff to run his reelection campaign. With his domestic initiatives going nowhere, Trump will be gambling on foreign military triumphs for adulation. If he scores a victory, the news will show him celebrating with his Chief of Staff. If American forces suffer setbacks, he’ll shift the blame by ordering Kelly to fire the “losers” in high command. Either way, he needs the General by his side.

David Boaz, executive vice president of the libertarian Cato Institute:

Kelly will remain until after the 2018 election, when he can plausibly say he righted the ship. Kelly will stay on because he’s a Marine and he took an oath to support and defend the Constitution of the United States. True, he’s likely never dealt with a commanding officer who ran a chaotic ship or whose family members are inserted in the chain of command. But he will repeat, “Duty, Honor, Country” during trying moments. It may turn out that, like Gen. Alexander Haig [chief of staff under Richard Nixon and Gerald Ford], Kelly will execute a smooth transition to a new president.

Ron Klain, former chief of staff to Vice Presidents Al Gore and Joe Biden:

Kelly lasts until mid-November, 2018. Chiefs of Staff leave the White House two ways — they jump, or they are pushed.  Kelly is not a jumper. He has stuck with Trump this far and believes that, along with Defense Secretary James [Mattis], he has kept the President from doing even worse things. He passed on resigning in protest over the James B. Comey firing, and took this job despite the President and his people being under criminal investigation and the White House continuing to lie about the facts. Trump boasted that he personally picked Kelly. Dumping him would be admission of a mistake. That said, if Republicans suffer a drubbing in 2018 — as I expect they will — it will be time for another reset. At that point, Trump’s die-hard supporters will demand that Trump be allowed to “be Trump” (upset that Kelly kept the leash too tight), and less devoted allies will hope for yet a different Trump minder (upset that Kelly allowed the leash to be too loose).

John Podesta, former chairman of Hillary Clinton’s 2016 campaign and former chief of staff to President Barack Obama:

November 2018. Trump can’t afford to lose him before then. Kelly is too much of a patriot to abandon the field. But after the midterm election, all bets are off.

As for the Guesstimator, we doubt that Kelly will last until the midterms. This White House is suffused with an unstable gas, and that miasma will likely explode before next summer. If Kelly does persevere to fall 2018, the prediction here is that he will be working for a different president.

How long will Kelly’s tenure as chief of staff last? Submit your own guesstimates for this question below. (If the form is not displaying, click here.) The reader with the best guesstimate will receive a free “Democracy Dies in Darkness” T-shirt. (Want to suggest a question for the Guesstimator? Click here.)