Russia's invasion of Ukraine in February demonstrated just how toothless and impotent the UN has become. Its system is too weak to take deterrent action, and has become an instrument of manipulation by powerful states. Before it can have a positive impact, it needs thorough and comprehensive reform.
There are certainly some flaws within the UN that the invasion of Ukraine has exposed, but other features of its system have retained their usefulness. The charter provided Ukraine with an irrefutable legal standard of aggression that became the basis for international support, while Guterres has added his voice and prestige to condemnations of the Kremlin. The UN has provided a forum of acknowledged international legitimacy - through this, nations have denounced Russian aggression.