MUNICH — It's called the Munich Rule: engage and interact; don't lecture or ignore one another.
But this year, at the 60th Munich Security Conference (MSC), two of the most talked-about people weren't even here.
That included former US President Donald Trump, whose possible return to the White House could throw a spanner in the work of the transatlantic relationship, which lies at the heart of this premier international forum.
And Russia's President Vladimir Putin, who was vehemently blamed by one world leader after another for the death of his most prominent critic Alexei Navalny, not to mention his full-scale invasion of Ukraine, which continues to cast a long dark shadow across Europe and far beyond.
The staggering news of Navalny's death, which broke just hours before the conference kicked off on Friday, underlined again the perilous unpredictability of a world carved up by multiple fault lines and entrenched interests.
"We live in a world where there is more and more confrontation and less co-operation," regretted the EU's High Representative for Foreign Affairs and Security Policy, Josep Borrell. "The world has become a much more dangerous place," he told me as the conference drew to a close on Sunday.
"Lose-Lose?" was the maxim of this year's gathering, at a time of deepening geopolitical tensions and jarring economic uncertainties.
The MSC's annual report warned that it could give rise to "lose-lose" dynamics among governments, "a downwards spiral that jeopardises co-operation and undermines the existing international order".
"I think this has been the conference of a disordered world," reflected David Miliband, the CEO and president of the International Rescue Committee (IRC).
"It's a world dominated by impunity, where the guardrail stabilisers are not working and that's why there's so much disorder, not just in Ukraine and in Gaza and Israel, but more widely in places like Sudan, whose humanitarian crisis isn't even getting on the agenda," he said.
This issue of impunity, one of the toughest of political challenges, was suddenly transformed into a poignant personal story when Navalny's wife, Yulia Navalnaya, unexpectedly appeared on the conference's main stage in the grand Bayerischer Hof hotel to condemn Russia's president and urge the assembled presidents, prime ministers, defence chiefs and top diplomats to bring him to justice.
Her remarkable composure and clarity stunned the packed hall, which gave her a sustained standing ovation before and after she spoke with palpable pain.
This year Russia, as well as Iran, weren't invited to Munich because the organisers assessed they weren't "interested in meaningful dialogue".
In MSC forums gone by, vitriolic speeches by Russia's veteran Foreign Minister Sergei Lavrov angered and electrified the main hall, and Iran's visible presence highlighted the rivalries and risks in urgent need of resolution.
The imperative of continuing hefty Western military and financial assistance to Ukraine was underscored repeatedly by Ukraine's President Volodymyr Zelensky, who exhorted participants to act, as he rushed from one high-level meeting to the next.
"The year of 2024 demands your response - from everyone in the world," he beseeched delegates when he spoke from the top podium.
The US's pivotal support was uppermost in his mind as a vital security package, amounting to $60bn (£48bn), is being held up by a US Congress where Republican lawmakers are increasingly divided over whether to keep backing Kyiv in its fight.
Back home in Ukraine, soldiers are even running out of bullets on front lines.
US delegates in Munich, including Vice-President Kamala Harris, were at pains to insist that she and President Joe Biden would not abandon Ukraine, nor America's leadership in global affairs.
But with US elections just nine months away, Trump is already shaping the polarised political debate in Washington and reviving anxiety that he could pull the US out of the Nato military alliance and other international commitments.
"They know what they need to do but they can't get it done, and that's the gap that has to be filled," was how Miliband assessed pledges voiced by the US and European allies in Munich.
Others were even more stinging in their criticism.
"Lots of words. No concrete commitments," posted Nathalie Tocci, Director of the Institute of International Affairs, on X, formerly known as Twitter. "It's a sad MSC2024."
The gaps were even more glaring when it came to the devastating Israel-Gaza war, which erupted after Hamas's murderous assault on southern Israel on 7 October.
Israel's military operations are causing a staggering number of civilian casualties and have ravaged much of this coastal strip.
"We have seen a really great interest from the international community and the world leaders who have gathered here in Munich that they would like to see a serious ceasefire and a substantial amount of international aid into Gaza," Palestinian Prime Minister Mohammad Shtayyeh remarked in an interview.
But Israeli delegates, including former peace negotiator Tzipi Livni, doubled down on the need to keep pressing forward.
"I'm a political opponent of [Prime Minister Benjamin] Netanyahu, but I support the war in Gaza," she emphasised in a session, which also included Shtayyeh and the Jordanian Foreign Minister Ayman Safadi.
"I support the strategic need to eliminate Hamas as a terrorist organisation and as a regime," Ms Livni said.
This year's MSC marked a record attendance: more than 900 participants including some 50 heads of state and government from around the world, more than 100 ministers, as well as representatives of think-tanks, non-governmental organisations and leading businesses.
Top spooks, feminist foreign ministers, climate warriors, Iranian activists, weapons experts, technology wizards and more - all gathered for their own get-togethers on public stages and in private rendezvous and hushed huddles.
It all underlined how the world's understanding of "global security" keeps shifting shape.
Over the decades, this forum - born in 1963 in a Cold War quest for peace and prosperity - has often been a venue for real-time diplomacy, too.
But in a year marked by worry over "lose-lose dynamics" Munich was a place for a lot of talking and taking stock as the world nervously wonders where the next blows will fall. — BBC