The UN maybe an ineffectual organization as you point out. But what is the alternative: the law of the jungle where stronger nations do anything they want to weaker ones? Occasionally, it is a convenient tool for the US and its Western partners; for example where they tried to claim that resolution 1441 gave them the right to invade of Iraq in 2003.
There is no military solution to the Israel-Palestine conflict only a political one. The only way for the people of Israel and Palestine to be able to live in peace is for a 2 state solution. The state of Israel and state of Palestine living side by side with each recognizing the others right to exist. The alternative is a never ending cycle of bloodshed.