In principle the UN is a great idea. Jaw jaw not war war.
The trouble is that its dysfunctional. the Five World War II victors (Russia, Britain, France, USA and China) each have a veto that they can scupper any resolution with. there are moves afoot to give some special recognition that the world has changed in the last sixty years and that other countries are now influential, including Germany, Japan, Indian and Brazil but I think the existing veto holding countries would veto such a change.
If we had a better working relationship with Russia and China we could get a lot more done at the UN to get robust motions of issues that might otherwise lapse into war.
Another problem is that Israel is always beleagured by the fact that there are a lot more Arab votes (one per country) than there are Israeli, so Middle East issues are always hard to resolve in the forum.
We need to use our voices on the other main international fora such as the World Bank and the IMF and occasional conferences such as Bretton Woods in the 1940s. To do so effectively needs having wholesome good ideas and presenting them clearly and winning people and nations to them. In the near future an example of a cause that needs promoting is to get a fresh and wise and fair monetary dispensation for the world economy to supercede Bretton Woods and to stabilise affairs after the 2008 crisis. It is a vital job but first we need clarity and I think this website is edging towards it.