Which is one reason why the United Nations was stronger than the League of Nations? It had a security council to respond to global crises. It focused on militaristic, rather than peaceful, solutions. It allowed only the most powerful nations to join. It had more wide-ranging international goals.
There are many reasons for this, The USA was a member of the league.And the UN to take much stronger action to prevent conflict where the failure of the UL was highlighted in the Japanese invasion of manchuria And the UN had the power of putting in peacekeeping Forces to try and prevent conflict or an escalation of conflict. However it would be wrong to assume that such actions have always been successful.