The United Nations is a great organization but it needs reform regarding many treaties, particularly the Rome Statute. The member states have a chance every three or four years to sit, to decide, to vote, and to change, add, modify, and reform. This could not be done this way. It needs effort. It needs people to speak loudly to their government, and for their representatives to go and ask for the reforms.
I cannot understand that the Security Council can meet in an hour and make a decision to invade certain countries, but it cannot make a decision in three years to stop war in a country. The international community—including even Russia and China, which are opposing the stopping of war and have suppressed three Security Council resolutions—agreed to disarm the Syrian regime of chemical weapons in just a few days.
Why are they not acting? It's a lack of political will and interest.