The United States keeps nuclear weapons to deter nuclear attacks from other countries. However, it also reserves the right to use its nuclear weapons first—for example, in response to a non-nuclear attack by Russia, China, or North Korea. These countries also have nuclear weapons and could respond to a US nuclear attack in kind. The United States will have started a nuclear war—with potentially devastating consequences.
A no-first-use policy—in which the United States declares it will never use nuclear weapons first—would remove the ability of the United States to start a nuclear war, increasing global security.
Taking first use off the table makes us all safer.