Facing an aggressive Russian or Chinese regime, armed with nukes and more or less modern conventional forces doesn't leave a lot of options for Western politicians. Specifically Putin have reacted with raising stakes and escalation every time he's been challenged. If the other side reacts in the same way a nuclear war is inevitable. There is no magical "leadership" that can resolve complicated conflicts without taking enormous risks with the future of humankind.
The war in Ukraine was handled by the West politicians quite well IMHO. They supplied Ukraine with enough weapons and money to be able to free big parts of occupied territories and to stop any future Russian advances.