It has never been so easy to gather evidence of war crimes. Satellite images now achieve such a level of detail that they can show individual bodies on the streets. Smartphones have been used by the Ukrainians to capture photographs of atrocities and publish them online. Investigators will have no shortage of material to prove that Vladimir Putin’s forces are guilty of murder, rape, and the brutalisation of the Ukrainian population and that the Kremlin’s denials are mendacious.

None of this is likely to make it any easier to hold Putin and his regime to account internationally, however, in part because Russia retains a veto as a permanent member of the UN Security Council. Ukraine’s president, Volodymyr Zelensky, addressed the UN yesterday, saying this gave Russia the “right to sow death”. The massacres in towns such as Bucha have only highlighted how toothless the body has become.

When the UN was set up in 1945, the hope was that it would avoid the deficiencies that plagued its predecessor, the League of Nations, which was powerless to stop the slide into the Second World War. To be fair to the UN, there has not been another major global conflict since it was founded – although that might have rather more to do with the proliferation of nuclear weapons than any high-minded discussions in New York.

Aside from the embarrassing tendency for the most brutal regimes in the world to acquire seats on UN human rights bodies, at the heart of the problem is the Security Council. Populated by the victors of the Second World War, the UK and France retain a leading role, while larger economies such as Japan have no permanent seat. The presence of China and Russia, meanwhile, means that two nations that have long been guilty of terrible breaches of international norms can block moves to discipline them.

There does not seem to be much appetite for reform, although countries such as India and Nigeria occasionally complain about the lack of influence accorded to rising powers. It is also not clear what sorts of reform would be beneficial, given the obvious risk that enlarging the central decision-making body would make it even harder for decisions to be made.

Perhaps the rot at the heart of the UN mattered less in a world where the United States was still the global hegemon, or even when the US and USSR were locked in a cold war. Now it looks positively dangerous.