They have solved tens of thousands of international issues. Not all have been earth shattering by your standards but many involve health issues, food production, sharing of resources, education, child welfare, international custody....
Now that's funny stuff. The USA provides medicine, food, resources, education, child welfare, etc and etc much more than the UN ever thought of. It is very ignorant to give the UN credit for doing far less than the USA has done for others over the history of our nation.
Do you understand what international issues are? It does not involve handing out CARE packages. The UN is involved in ensuring international cooperation in sharing medical breakthroughs, health initiatives, sharing farming technologies.
There are a billion starving people in the world and the UN has a key role in removing international impediments to feeding the masses
No wonder the Conservatives want to shut it down