And as age changes the physical condition and interactions of weapons' components and materials, the probability will increase that -- without a renewal of periodictesting -- such defects will increase in severity and number.
For most of the nuclear era, successive U.S. administrations of both political parties regarded periodic nuclear testing as essential to the maintenance of a safe, reliable and effective nuclear deterrent.
Without periodic, realistic testing, it is not scientifically possible to assure with high confidence that existing nuclear weapons are as safe and reliable as we know how to make them.