Link: http://politicaltheatrics.org/2009/10/24/happy-united-nations-day/

“Ambassador Charles W. Yost cast the first U.S. veto in 1970, regarding a crisis in Rhodesia, and the U.S. cast a lone veto in 1972, to prevent a resolution relating to Israel. Since that time, it has become by far the most frequent user of the veto, mainly against resolutions criticizing Israel. This has been a constant cause of friction between the General Assembly and the Security Council, as seen with the 2003 Iraqi war which was not endorsed by the UN.”