Back in 2001, France floated a proposal that the five permanent members of the United Nations Security Council (P5) should voluntarily refrain from using their veto power when dealing with mass-atrocity crimes.

And now, in the lead-up to the commemoration of this year's 70th anniversary of the U.N., French President Francois Hollande's government is actively pursuing the idea again. Could such an arrangement really work?

The predictable initial response is to dismiss the possibility out of hand. As Australia's wartime prime minister, Ben Chifley, once remarked, "The trouble with gentleman's agreements is that there aren't enough bloody gentlemen."