UN chief Antonio Guterres has warned for years about the impact of divisions at the Security Council. Now the gaps will be tested again with a rift between France and its US and British allies.
Ministers of the five veto-wielding nations on the UN's most powerful body -- Britain, China, France, Russia and the United States -- will meet together Wednesday during the annual week of diplomacy, with the Taliban takeover of Afghanistan high on the agenda.
"If we want to avoid Afghanistan becoming a haven for global terror then the international community -- including Russia and China -- needs to act as one in its engagement with the Taliban," said British Foreign Secretary Liz Truss, who is leading the meeting.
China and Russia have quickly moved to work with the Taliban but have withheld recognition. Russia, China and the United States serve on a credentials commission that is reviewing the Taliban's request to address the General Assembly as Afghanistan's representative.
France, Britain and the United States are largely united on the way forward in Afghanistan, even if some Europeans voiced misgivings over President Joe Biden's withdrawal of US troops that allowed the Islamist insurgents to take power.
But French Foreign Minister Jean-Yves Le Drian has so far refused talks with his US and UK counterparts, although he shook hands with Secretary of State Antony Blinken at a larger meeting on Libya.
France has been furious over Australia's cancellation of a mega-contract for conventional submarines and decision to buy US nuclear versions amid rising tensions with China.
Australia will have access to the US nuclear technology as part of a new three-way alliance with Washington and London.
- Anger vs. interests -
The three Western nations on the Security Council have clashed before, notably with France's strident objections to the 2003 US invasion of Iraq, but during the Cold War and again in recent years they have largely been in lockstep.
"Eventually these disagreements could get worse, showing that this old design of international security needs to be revised," said Bertrand Badie, an international relations expert at the Sciences Po university in Paris.
Donald Trump's turbulent presidency and Britain's divorce from the European Union drew concern from France, but the three Western powers have almost always been united at the Security Council, with Russia and China exercising their veto notably on Syria.
Even if President Joe Biden succeeds in calming France's fury, Paris could see less incentive to rally behind the US position when it disagrees.
Badie expected Russia and China to seek ways to make inroads.
"Attempts at diplomatic phishing will of course be aimed at France," Badie said.
But many doubted a significant shift by France, the oldest ally of the United States which largely sees eye to eye with Washington on key questions from the rise of China to the threat of Islamist extremism.
"I don't think that the submarine deal will torpedo the P3," said Richard Gowan, who follows the United Nations for the International Crisis Group.
"France is stuck with the Anglo-Saxons, even if it is a complicated relationship."