The comprehensive test-ban treaty makes very good strategic sense for the United States and the world. The next American president should build on Bill Clinton's signing of that treaty, as well as George W. Bush's tacit compliance with its strictures, and send it to the US Senate for ratification. It makes sense whether Iran tests its own nuclear weapon in the coming years or not; either way, Washington will need more capacity to apply more pressure on states like Iran, and the treaty could help it garner international support for such pressure. American ratification of the treaty might also be part of a deal by which India and Pakistan agree not to do more testing themselves, joining the United States in a pledge of future restraint.