From NPR.

President Trump has announced that the U.S. will start testing nuclear weapons “on an equal basis” with Russia and China in what could mark a reversal of decades-old policy.

The U.S. hasn’t conducted a test of a nuclear weapon since 1992. Instead, it uses scientific experiments and computer simulations to make sure its bombs still work. The voluntary test moratorium has been in place since the end of the Cold War.

It’s not entirely clear what resuming testing “on an equal basis” means. Russia and China haven’t tested nuclear weapons in decades — though both nations have been modernizing their arsenals in recent years.