The United Nations needs to be more muscular and united if it wants to stay relevant in tackling the world’s multiple escalating crises, a group of elder statesmen founded by Nelson Mandela said Friday. Former world leaders in the group known as ‘The Elders’ told Associated Press executives that the U.N.’s most powerful organ, the Security Council, needs to unlock the paralyzing impact of its vetoes – and that the secretary-general of the 193-member world organization needs to speak out more clearly on violations of international law. The United Nations was founded on the ashes of World War II…