Above it all
According to the United Nations Charter, the exact size and strength of a peacekeeping deployment is agreed to by the government of the country on whose territory that deployment will occur. What this means is that if a UN-mandated peacekeeping force were to be sent to Lebanon, for example, Beirut would have final say over these matters. Why is it, then, that the Israeli ambassador to the UN, Dan Gillerman, ruled out any major UN involvement in any potential international force in Lebanon? Since when does the aggressor have a say over who is allowed into the state it is aggressing against? Of course, Hezbollah, as a non-state actor (even if it has representation within the Lebanese government), wouldn't be consulted and would have to accept whatever force enters Lebanon. Still, if we were to respect the logic by which Jerusalem operates, Nasrallah should have a right of say, or perhaps even veto powers (as Israel seems to have) on the size and composition of the multinational force.
This, of course, is an attempt to ensure that whatever force is deployed in Lebanon is to Israel's (and by default Washington's) liking. For the umpteenth time in the recent past, Israel continues not only to flaunt dozens of UN resolutions but furthermore cannot even make an attempt to hide its contempt for the international body. It won't even allow UN participation in the investigation into the bombing of the UN post in Lebanon—and this in spite of the fact that four UN employees actually died in the attack. Yet again, with Washington's blessing, not only is it conceivable for Israel to think of itself as above the systems of laws that govern the rest of the world, but it can actually act as such.
There is a term used in political science to describe states that disregard international law and use brutal force to accomplish their political ends. They are called rogue states.