Mr. Obama also said, on behalf of the U.S., that “We will move forward with the ratification of the Comprehensive Test Ban Treaty” (CTBT). This is a profound mistake, as a ban on testing nuclear weapons would jeopardize American national security. Ten years ago this month the U.S. Senate rejected the treaty, and the reasons for doing so are even stronger today…

There were concerns a decade ago that the U.S. might be unable to safely and reliably maintain its own nuclear deterrent—and the nuclear umbrella that protects our allies such as Japan, Australia and South Korea —if it forever surrendered the right to test its weapons. Those concerns over aging and reliability have only grown. Last year, Paul Robinson, chairman emeritus of Sandia National Laboratory, testified before Congress that the reliability of U.S. nuclear weapons still cannot be guaranteed without testing them, despite more than a decade of investments in technological advancements.

Treaty proponents, nevertheless, believe the prospective benefit of ratification outweigh its risks and problems. And what, exactly, is the benefit of ratification?…

Iran and North Korea are already in violation of the Nonproliferation Treaty (NPT), which requires that they do not develop nuclear weapons. Yet for years the world has been unable to agree that these nations’ NPT obligations must be enforced. If the world can’t or won’t enforce the NPT there is no reason to believe it would be any more effective in enforcing the CTBT.