If the UN didn’t exist, would it be necessary to invent it today? The answer ought to be an immediate “yes”, what with the numerous conflicts, civil wars, refugee crises, food shortages, and challenges caused by climate change that are all ongoing. Of course there needs to be a global table at which these issues can be discussed, pressure exerted and moral weight brought to bear. And yet when it comes to the catastrophic situation in Ukraine, the UN leadership has appeared to be alarmingly absent – to the extent that it has been described as “the biggest crisis” in the UN’s history. Yes, UN Secretary General Antonio Guterres has made statements, such as this one in mid-March: “Ukraine is on fire and being decimated before the eyes of the world. This tragedy must stop. We need an immediate cessation of hostilities and serious negotiations based on the principles of the UN Charter and international law.” He added: “I will continue to highlight the desperate plight of the people of Ukraine as I am doing again today.” But in terms of mediating an end to this war, or attempting to do so, it has been state actors such as France and Turkey that have stepped forward. A group of more than 200 former senior UN staffers have been so worried at the prospect of the organisation “becoming increasingly irrelevant and, eventually, succumbing to the fate of its predecessor, the League of Nations, with the human losses and material destruction that went with it” that they wrote a letter to Mr Guterres saying just that on April 15. The signatories do not want to launch a full-on attack on the Secretary General. But their dismay at what the organisation has not been doing is clear. Their letter states: “We want to see a clear strategy to re-establish peace, starting with a provisional ceasefire, and the use of the UN’s capacity for good offices, mediation and conflict-resolution. That could include visits to the conflict-stricken areas, discussions with the opposing sides, even moving your own office temporarily to Europe, closer to the urgently needed negotiations and, thereby, indicating the UN’s resolve to address this major crisis head-on.” One co-signatory, Mark Seddon, who was a speechwriter for former UN secretary general Ban Ki-moon and is now the director of the Centre for UN studies at the University of Buckingham in the UK, tells me: “There’s an enormous groundswell among current and former UN staff, who have been watching with a real degree of concern that the SG has not been up and central, visiting Moscow and Kyiv, and taking some degree of personal risk in order to uphold the UN Charter.” Another co-signatory, former UN assistant secretary general Andrew Gilmour, has pointed out that every single former leader of the organisation had “left no stone unturned to stop an appalling war”. Mr Gilmour mentioned Dag Hammarskjold’s efforts to stop the Suez War in 1956, U Thant’s crucial behind-the-scenes discussions with then US president John F Kennedy and Soviet leader Nikita Khrushchev during the Cuban Missile Crisis, and Kurt Waldheim’s intervention in the Yom Kippur War of 1973. He also said of two later secretaries general: “Perez de Cuellar in 1991 and Kofi Annan in 1998 went to Baghdad to plead with Saddam Hussein to pull back. They both knew that they were rather making fools of themselves by doing so, because the odds of Saddam doing what they wanted him to do were always very small. But they took the view that it didn’t really matter if they were made to look a bit ridiculous. The point was to try.” That Mr Guterres, a second-term SG – who cannot seek re-election and therefore has little to lose – has not been seen to try hard enough thus far, has caused consternation. All of this appears to have pushed him to action. At the time of writing, he is in the middle of a three-day trip to Russia and Ukraine, although that may not stop a second letter, which I understand is in the pipeline, from unhappy former UN staffers who were unable to sign the first one from being sent to Mr Guterres. A primary concern, I’m told, is that while Mr Guterres may make some progress on the humanitarian front, in terms of food aid and safe passage for civilians, for instance, the suspicion is that he appears to be unwilling to lay his reputation on the line to work for a political solution. “What’s the politics of it?” asks one former staffer. “How hard is he pushing for a ceasefire?” Mr Guterres can’t keep blaming his previous lack of concrete efforts on paralysis in the UN Security Council, where the “P5” – China, Russia, the US, UK and France – each have a veto, says the ex-staffer, “because that’s always been the case”. As it happens, the UN General Assembly was due to vote on Tuesday on a resolution that would require members of the P5 to justify any future use of their veto. That may be a small step in the right direction, but even if passed it could not force any P5 member to account for itself, and in any case will have next-to-no bearing on the current crisis. Being UN secretary general is in many ways a thankless job, and Mr Guterres has won praise for his tireless advocacy on climate change in particular. But a world in which the use of nuclear weapons cannot now be ruled out needs him to assume a far bigger role on the global stage. He may have little formal legal power, but as Mr Gilmour pointed out: “He has a lot of moral power.” The signatories, he continued, with typical British understatement, “are very much hopeful that he will do what his predecessors always did". With peace in Ukraine and the future credibility of the UN hanging in the balance, the rest of us must fervently hope so too.