President Trump's boast last night that he has a "bigger & more powerful" Nuclear Button (caps, Trump's) than North Korea has some administration insiders worried that we could blunder into war.

• "Every war in history was an accident," said one administration insider. "You just don't know what's going to send him over the edge."
• The "him" was Trump, but could also refer to North Korean leader Kim Jong-un, who started the "nuclear button" exchange with a New Year's Day speech on Monday in which he said: "The U.S. should know that the button for nuclear weapons is on my table" (desk).
• The N.Y. Times' succinct homepage headline: "Trump Taunts Kim."

But, but, but: Trump insiders caution that the media tends to over-interpret and over-cover statements that Trump has made just to stir the pot, and with little prior thought.

• Their view is basically: Sometimes, a tweet is just a tweet.

Why it matters: The danger here is that Kim is also an unpredictable actor, and not one fully understood by U.S. intelligence.

• As one outside adviser to the West Wing told me: "This is the most important issue on the president's desk. We are in a hair-trigger environment. And this is potentially a shooting war with nuclear risk."
• The adviser added: "What intel analysis or foreign policy advice leads to employing this as a tactic?"

Be smart: Some West Wing insiders remain convinced that the risk of war is higher than most outsiders realize.

Reality check: No button — just a football and a biscuit ... "[T]he president doesn't actually have a physical button," by AP's Matthew Pennington notes:

• "The process for launching a nuclear strike is secret and complex and involves the use of a nuclear 'football,' which is carried by a rotating group of military officers everywhere the president goes and is equipped with communication tools and a book with prepared war plans."
• "If the president were to order a strike, he would identify himself to military officials at the Pentagon with codes unique to him. Those codes are recorded on a card known as the 'biscuit' that is carried by the president at all times. He would then transmit the launch order to the Pentagon and Strategic Command" (USSTRATCOM, located at Offutt Air Force Base near Omaha, Neb.)

Same for Kim ... Per the N.Y. Times: "[O]fficials ... dismissed Mr. Kim's comment that he now has a 'nuclear button' on his desk as a rhetorical flourish"

• "Currently, Mr. Kim cannot launch a weapon in seconds, as his declaration seemed intended to suggest. All of the tests he has conducted of intercontinental ballistic missiles have involved liquid-fuel weapons that take hours, sometimes days, to prepare for a launching."
• Go deeper ... "Here's how Trump launches a nuclear weapon," by Axios' Shannon Vavra.

After Trump's Twitter tantrums yesterday — calling for the jailing of a political opponent and bragging his nuclear button is bigger than North Korea's — CNN used its powerful platforms and people to suggest the president is mentally unstable.

• Jake Tapper started his 4 p.m. show, "The Lead": "President Trump is kicking off 2018 by going on Twitter, blasting Democrats, calling for a political opponent to be thrown in jail, demanding a potential witness be investigated, and praising himself. So, no New Year's pivot, apparently."
• Brian Stelter opened his late-night media newsletter, Reliable Sources (which had the subject line "Trump's fitness"): "There's a word for this. Madness."
• Stelter on "Anderson Cooper 360": "What would we say if the leader of Germany or China or Brazil posted tweets like Trump's? How would we cover it? We'd say: That person is not well. We'd wonder whether that person is fit to hold office."
• And a banner on a special 10 p.m. Tapper edition asked: "ARE WE CLOSER TO NUCLEAR WAR THAN EVER?"
• Tapper: "None of this [is] normal, none of this [is] acceptable, none of this [is] frankly stable behavior."

Why it matters: Trump has been known to watch CNN at that hour, and Stelter ended his item: "Was Trump watching?"

• Either way, 2018 is off with a familiar bang: The president trashing the media, and the media trashing him.

"For decades, those living in Iran's provincial towns and villages were regarded as the backbone of the country's Islamic regime. They tended to be conservative, averse to change and pious followers of the sober Islamic lifestyle promoted by the state," N.Y. Times Tehran bureau chief Thomas Erdbrink writes:

"In less than a decade, all that has changed. A 14-year drought has emptied villages, with residents moving to nearby cities where they often struggle to find jobs.""Access to satellite television and, more important, the mobile internet has widened their world."Be smart: These small town have now led a rolling uprising that has thrown Iranian politics and life into chaos. And they have done the unthinkable: unified a lot of America leaders in cheering them on.

CFR President Richard Haass tells me that the title of his book a year ago, "A World in Disarray," actually understated the situation.

• Haass is out this week with a paperback edition that includes a new, nine-page Afterword: "Things have become even worse that I had imagined. Disarray is greater than expected."

Key points Haass added for this edition:

• The Trump administration is a significant cause of increased disarray in the world: "Trump is the first post-WWII president to view the burdens of world leadership as outweighing the benefits. The United States has changed from the principal preserver of order to a principal disrupter."
• How this came about is unprecedented: "History suggests great powers and the international orders they are associated with inevitably fade.""[S]ome powers exhaust themselves through overreach abroad, underinvestment at home, or a mixture.""For some other powers, their privileged position is usurped by the emergence of one or more new stronger powers."[T]he United States has now introduced a third means by which a major power forfeits international advantage. It is abdication, the voluntary relinquishing of power and responsibility."
• "America First was not well received by American allies."
• "There is no alternative great power willing and able to step in and assume what has been the U.S. role. China is often suggested, but its leadership is focused mostly on consolidating domestic order and maintaining artificially high rates of economic growth, lest there be popular unrest.""There is no other candidate…The cold truth is that the alternative to a U.S.–led international order is less international order."
• Go deeper.

The unsurprising announcement by Senate President Pro Tem Orrin Hatch (R-Utah), 83, that he's retiring at the end of this term — and his likely replacement by Mitt Romney, who yesterday changed his Twitter location to "Holladay, UT" — is "another political setback for Mr. Trump," per N.Y. Times' Jonathan Martin:

• "Romney's potential ascent is particularly alarming to the White House because the former presidential candidate has an extensive political network and could use the Senate seat as a platform to again seek the nomination."
• "Even if he were not to run again for president, a Senator Romney could prove a pivotal swing vote, impervious to the entreaties of a president he has scorned and able to rally other Trump skeptics in the chamber."

Salt Lake Tribune: "[O]ne Romney confidant ... said Tuesday was 'Orrin's day' and the Romney circle didn't want to intrude on that [with a campaign announcement]. But the trajectory seems set."N.Y. Times Quote of the Day ... Hatch: "I was an amateur boxer in my youth, and I've brought that fighting spirit with me to Washington. But every good fighter knows when to hang up the gloves. And for me, that time is soon approaching."

"One of the biggest names in Silicon Valley is placing a moonshot bet on bitcoin," the Wall Street Journal's Rob Copeland writes on A1:

• "Founders Fund, the venture-capital firm co-founded by Peter Thiel, has amassed hundreds of millions of dollars of the volatile cryptocurrency."
• "The bet has been spread across several of the firm's most recent funds, ... including one that began investing in mid-2017 and made bitcoin one of its first investments."
• Why it matters: "Relatively few mainstream investors have bought large sums of bitcoin, scared off by concerns about cybersecurity and liquidity, as well as more mundane fears of investment losses."
• The takeaway: "Founders and Mr. Thiel, 50 years old, are well-known for early investments in companies like Facebook Inc. that sometimes take years to come to fruition. The bitcoin bet is quickly showing promise."

PEOPLE magazine's forthcoming cover story, with the announcement yesterday that Hoda Kotb (HOH'-dah KAHT'-bee) will join Savannah Guthrie as co-anchor of NBC's "Today":

"Our fresh start: One month after Matt Lauer's shocking dismissal, the show's first-ever female anchor team open up about friendship, forgiveness and what's next," by Charlotte Triggs:

• Savannah: "Hoda gets up at 4 o'clock in the morning even on Saturday."
• Hoda: "I've had 53 years of sleep, okay? I'm good."

This is TODAY,

on NBC.

Cover story of the forthcoming N.Y. Times Magazine ... "The Case for the Subway: It built the city. Now, no matter the cost — at least $100 billion — the city must rebuild it to survive," by Jonathan Mahler:

• "For all the changes in transportation technology since the first tunnels were dug ... the subway remains the only way to move large numbers of people around the city."
• "Today, New York's subway carries close to six million people every day, more than twice the entire population of Chicago. The subway may no longer be a technological marvel, but it continues to perform a daily magic trick: It brings people together, but it also spreads people out."
• "It is this paradox — these constant expansions and contractions, like a beating heart — that keep the human capital flowing and the city growing.
• Why it matters: "New York's subway has no zones and no hours of operation. It connects rich and poor neighborhoods alike. The subway has never been segregated. It is always open, and the fare is always the same no matter how far you need to go.

Go deeper.

"Inside an ESPN President's Shocking Exit (and Bob Iger's Possible Role)," by James Andrew Miller, who wrote the book on ESPN, for Hollywood Reporter:

• John Skipper cited "substance addiction" as the reason for abruptly stepping down in December, but both his actions before the announcement and Disney's incentives to push him out suggest a different narrative."
• "In the aftermath of Disney's Dec. 14 announcement that it will acquire significant parts of 21st Century Fox, Iger revealed he will stay at Disney through 2021, not only apparently taking him out of the running for the Democratic nomination for president, but also giving him more time to deliver to the Disney board a designated successor for himself.
• "And what better proving ground is there in the Disney constellation than ESPN? ... Get the ESPN job, hit that pitch out of the park, and you've automatically earned a spot on the shortlist to follow Iger."