Nearly lost in the week’s news — the nomination of an iconoclast to run the nation’s health agency who is at odds with the nation’s health experts, and an account of the former congressman chosen to be the chief law enforcement officer who, according to witnesses, had sex with a 17-year old near a pool — was a small item that has the potential of triggering a nuclear war.

Amid the parade of Donald Trump’s Cabinet nominees, another president, sitting 5,666 miles from Mar-a-Lago, just adjusted the threshold Russia considers reasonable for the use of nuclear weapons. The new Cold War that Trump is two months from inheriting just got chillier.

Put aside any contemplation about the relationship between the incoming American president and the longtime Russian president, though Trump apparently believes that he can end the war in Ukraine in a nanosecond, or in a week at most. Vladimir Putin just implemented language that permits the world’s second-biggest nuclear power to employ nuclear weapons to respond to a conventional-weapons attack that creates a “critical threat” to its “sovereignty and territorial integrity.”

World War I began with less provocation than that — and Russia’s mobilization in support of its Serbian ally following the assassination of the heir to the Austria-Hungarian throne was an essential element of the slide to catastrophe in the summer of 1914.

Each American missile that Ukraine sends into Russian territory is a potential 21st-century equivalent of the Browning-engineered handgun attack on Archduke Franz Ferdinand. That is what Putin is suggesting in his apparent response to President Joe Biden’s decision to permit Ukraine to send American-made long-range missiles into Russian territory.

“This can’t be a good thing for humanity,” said Arnout van der Meer, a Colby College historian. “Since the first Trump presidency, we have seen a desire on both sides of the Atlantic to proliferate — and not to go the other way. This isn’t just about Ukraine. It’s part of a larger realignment of thinking about nuclear weapons. It reflects the new balance of power that Putin is seeking.”

At a time when so many dangerous dominos are falling across the world — some in the United States, where divisions not seen since the Civil War produced a bitter election; some across the globe, where populist leaders are storming the gates of government; some in the far eastern plains of Europe where the Ukraine war just passed the 1,000-day mark — the escalation of nuclear doctrines isn’t a comforting thought.

Indeed, it is quite the opposite.

When Putin first floated his nuclear balloon more than two years ago, Biden recognized the peril. “For the first time since the Cuban missile crisis,” he said, “we have a direct threat of the use [of a] nuclear weapon if, in fact, things continue down the path they are going.”

Biden’s additional October 2022 remarks — why didn’t anyone notice that his comments came almost 60 years to the day after American reconnaissance planes noticed the presence of missiles 90 miles from Florida? — could be repeated today, though Trump has been silent:

“We’ve got a guy I know fairly well,” Biden said then. “He is not joking when he talks about the potential use of tactical and nuclear weapons, or biological or chemical weapons, because his military is, you might say, significantly underperforming.”

It is one of the peculiar niceties of diplomacy that nations prepare, and sometimes publish, their military doctrines.

From 1919 to 1932, following an initiative from Winston Churchill, British governments drafted a 10-Year Rule document setting out the likelihood of a major war in the following decade. Since 1986, the United States has prepared National Security Strategy documents; the George W. Bush administration used this congressional requirement to set out its preemptive war doctrine growing out of the response to the Sept. 11, 2001, terrorist attacks.

The United States also routinely publishes a National Military Strategy document. In a reference to Russia and China, the most recent one states that “for the first time in our nation’s history, the United States faces two major nuclear powers that may employ nuclear coercion as a way to meet their national objectives,” and adds, “What we do in the next few years is going to set conditions for victory or defeat in the next war.”

Putin’s series of doctrines — perhaps an effort to prepare for a new American president and his administration — is a frosty extension of that tradition.

The new Putin language says Russia could use nuclear weapons to attack countries that provide conventional weapons to be used against it — a change from the notion that Russian nuclear weapons would be used only in response to a direct attack by another nuclear power.

In short, if a nuclear power like the United States provides weapons to a non-nuclear country like Ukraine to attack Russia, then Russia has the right to use nuclear weapons against the United States. It is Putin’s way of drawing another red line to dissuade Western powers from aiding Ukraine. At every juncture where a power has crossed the red line thus far, nothing has happened.

“He’s changed his own doctrine multiple times,” said Benjamin Jensen, a senior fellow for future war, gaming and strategy in the International Security Program at the Center for Strategic and International Studies and a professor of strategic studies at the Marine Corps University School of Advanced Warfighting. “Every red line we thought would trigger a confrontation has not. We won’t know for decades what shaped his calculus.

“But,” he continued, “we do know he has a lot more escalation options before conducting a non-strategic nuclear weapons strike.”

Two additional major elements remain uncertain. One is whether it might be the equivalent of a major strategic change if Putin decides to use a nuclear weapon on his own territory against Ukrainian forces. Another is what Putin might be contemplating privately; as Jensen said, “The moments when we should be worried are when Putin says nothing.”

This age of uncertainty and certain peril is reminiscent of November 1914, two months into the First World War, when a letter written by Sigmund Freud set out the perils of his time, and ours.

“I and my contemporaries will never again see a joyous world,” he said. “It is too hideous. And the saddest thing of all is that it is precisely what psychoanalysis has led us to expect of man and his behavior.”

A Swampscott High School Class of 1972 member, David M. Shribman is the Pulitzer Prize-winning former executive editor of the Pittsburgh Post-Gazette.