Bureaucrats from 150 nations are ramping up efforts to impose gun control through international pact. Here in the United States, the United Nations Arms Trade Treaty has become the vehicle to drive an agenda that is deeply controversial because once a treaty is ratified by the Senate, it becomes the supreme law of the land. Last week, Secretary of State John F. Kerry — no friend of the Second Amendment — announced support for the treaty, which calls for international regulations on firearms, including personal firearms as well as military weapons. During the presidential campaign, President Obama was evasive about...