On a brisk Tuesday night in Washington, DC’s tony Cleveland Park neighborhood, hundreds of concerned citizens gathered at Washington National Cathedral to hear some unpleasant truths from former defense secretary William Perry.

Perry was there as part of the cathedral’s Nancy and Paul Ignatius Program to address what he believes is the very real danger of an accidental nuclear conflagration between the United States and Russia, now that relations between the two nuclear superpowers have deteriorated to their lowest point in the quarter-century since the fall of the Soviet Union.

Perry recalled his own experiences during the first Cold War, when, as a young man, he served in the Army during the occupation of postwar Japan, and later, when he served as undersecretary of defense for research and engineering under President Jimmy Carter, and, later still, from 1994–97, when he served as Pentagon chief under President Clinton.

California Governor Jerry Brown has written, “I know of no person who understands the science and politics of modern weaponry better than William J. Perry.”

Perry recalled that, during the first Cold War, both the United States and the USSR experienced multiple nuclear false alarms that could have resulted in planetary catastrophe.

Perry recounted one such incident that he experienced firsthand, when, in November 1979, during his time as undersecretary, he was awakened by a 3 am phone call from a watch officer at the North American Aerospace Defense Command (NORAD). The watch officer informed Perry that 200 intercontinental ballistic missiles had been launched at the United States by the Soviet Union.

It was quickly determined that this was a false alarm—but Perry noted that, because relations between the United States and the USSR were relatively stable at that time, there was reason to question whether the information from NORAD was correct.

But what if, asked Perry, such a false alarm had occurred during a time of heightened tension, as during the Cuba or Berlin crises, or even today?

Perry warned that the nuclear risk has not abated since the end of the first Cold War—indeed, the risk has only grown. Said Perry, “The likelihood today of a nuclear catastrophe is greater than during the Cold War.”

“Today, inexplicably to me, we are recreating the geopolitical hostility of the Cold War and we are rebuilding the nuclear dangers of the Cold War. We are doing this without any serous public discussion, or any real understanding of the consequences of these actions: we are sleepwalking into a new Cold War, and there is a very real danger we will blunder into a nuclear war.”

Following Perry’s address, Susan Eisenhower, a respected arms-control and Russian-affairs expert, appeared alongside former secretary of state John Kerry, former national security adviser Stephen Hadley, and Washington Post columnist David Ignatius for a discussion about a number of potential nuclear flash-points.

Eisenhower observed that today relations between the United States and Russia are so bad that it would be hard to imagine that an American president could extend an invitation to a Russian president to visit the United States—as when her grandfather invited Soviet leader Nikita Khrushchev to visit in 1959.

Eisenhower agreed with Perry that the situation that exists between the United States and Russia today is fraught with danger, which is why, she said, “I don’t understand why we are cutting off all the vital exchanges that keep US-Russian relations from dropping below an acceptable level.”

“Today we have no exchanges of any kind, we are punishing Russia, [and] we are punishing ourselves…. it would be catastrophic if we turn the Russian people against us.”

Yet the question remains: What will the consequences be if the warnings of Perry and Eisenhower continue to fall on deaf ears and the bipartisan consensus on Russia continues to be almost completely untethered from reality?

It hardly should need pointing out that the new Cold War is unfolding against the backdrop of a renewed assault on the P5+1 Iranian nuclear agreement. The assault, led by the Trump administration and abetted by the congressional war party, is taking place in spite of the fact that in mid-November the International Atomic Energy Agency (IAEA) confirmed, for the ninth straight time, that the Islamic Republic of Iran is in compliance with the Joint Comprehensive Plan of Action.

According to a recent report:

The confidential quarterly IAEA report, seen by several Western news agencies on November 12, said Iran “has not enriched” uranium above low levels and that its stockpile of enriched uranium was under the agreed limit of 300 kilograms.

The IAEA also said its inspectors faced no difficulties in accessing sites that they wanted to visit.

On Tuesday at the National Cathedral, John Kerry, a principal architect of the Iranian nuclear agreement, pushed back on the newly empowered critics of the agreement.

In the absence of a deal, “and without exaggeration,” said Kerry, “the likelihood is very high that we would have been in a conflict” with Iran.

“Iran was a threshold nuclear nation when we sat down to talk for the first time in 35 years,” said Kerry. But under the agreement, Iran went from 12,000kg of enriched uranium to 300kg. That, said Kerry, is the stockpile Iran has today and will have for the next 15 years, thanks to the agreement.

Still more, the Iranians agreed to keep the level of enrichment at 3.67 percent (down from 20 percent, which was the level of enrichment Iran had reached prior to the deal) for the next 15 years. Kerry noted that the international community is now able to trace “every ounce of uranium they produce in their mines for the next 25 years.”

“It is physically impossible to make a nuclear weapon,” said Kerry, “with 300kg at 3.67 percent enrichment.”

Kerry observed that, while many in Congress and in the administration are agitating to implement ever-greater sanctions on Iran (in order, of course, to destroy the deal), few are aware that the we have fewer sanctions in place against North Korea, which has roughly 20 nuclear weapons, than we have in place against Iran, which has none.

And so: What to do with the world on the nuclear brink, with the very real potential for an outbreak of perhaps simultaneous crises between the United States, Russia, Iran and North Korea?

As Perry pointed out, climate change is another looming catastrophe, but it is one of which the public is, for the most part, aware. Perry argued that, as is the case with climate change, “we need a program of public education” regarding the growing nuclear danger.

And for his part, Perry pledged to dedicate the remainder of his public career to the task.

In his recent book, My Journey at the Nuclear Brink, Perry writes: “Our chief peril is that the poised nuclear doom, much of it hidden beneath the seas and in remote badlands, is too far out of the global public consciousness. Passivity shows broadly.”

Finding, he said, his motivation in a wish that his grandchildren not have to live with the ever-present specter of nuclear catastrophe hanging like a Sword of Damocles above their heads, Perry has proved to be anything but a passive player in this continuing, and very troubling, drama.