Andrew Bast adds to Mark's takedown of David Rothkopf's bit of indiscriminate UN-bashing:
To begin with, Rothkopf repeatedly refers to the "U.N.," when it's clear that he's talking about just the Security Council, the instance of the organization that handles matters of international peace and security. But to reduce it to a mechanism for conflict resolution, as Rothkopf does, misses the point. The theory underpinning the composition of the council, rather than elementary, is a rather nuanced and high-minded concept in international relations known as collective security. Put simply, an attack on one member state constitutes an attack on all. The logic behind the theory is to create significant disincentives for aggression, thereby increasing stability among the society of states. The best example of collective security at work was the council's response to Iraq's 1990 invasion of Kuwait.
This is a good point -- that the complexity underlying the Security Council system is often taken for granted, or, worse, misinterpreted as simplicity. Now, one might quibble that the composition of the Council as it actually exists means in reality that an attack on one member state that is supported by a permanent member of the Security Council constitutes an "attack on all." But in this respect, one could even see the relative polarization of the Council's permanent members -- with the U.S., UK, and France often on one side, and Russia and China on the other -- as a sort of benefit. Every country in the world is probably an ally of one of these five, so an attack on any will be strongly dissuaded.
The problem, of course, is that aggression is not limited solely to state-on-state invasion, and that the same alliances that dissuade this sort of aggression can make it more complicated to take collective action to stop a country's internal strife (see, for example, Sudan). This dynamic, though, is not a fault of the construction, or peace and conflict function, of the UN Security Council; it is a development in geopolitics, with which international security norms, writ even larger than the Security Council, have not yet fully caught up. How to make "collective security" incorporate the safety and well-being of a particular state's citizens, without impinging on that state's sovereignty, is a question even bigger than the Security Council. As a mechanism for resolving conflicts and maintaining peace, the Council is in fact evolving along with international relations, as it has to -- but, as, say, the contrasting cases of Kosovo and the second Iraq war suggest, this progression is not a neat and linear one.
(image from flickr user Dipp under a Creative Commons license)
The invaluable IntLawGrrls blog 
If anything, I think of the Scooby Doo Five as a decent analog for the United Nations weapons inspectors: mobile and peripatetic, spooked by the astral, often kicked out of the amusement park, much derided but really fairly decent at digging out the truth.
The issue of halting settlement growth is crucial to achieving peace in Israel and Palestine. The Obama Administration has been refreshingly honest in emphasizing this point, but it is not going to throw Israel under the bus over it. Whatever pressure it exerts on Israel to stop building settlements will be related to the issue of settlement construction. If a juvenile attack on Israel's existence is somehow raised in the Security Council, I'm sure the United States will not shy from wielding its veto. To imply otherwise is simply creating a controversy that doesn't exist.