A more thorough explanation:

The Bureau of Arms Control is a department within the U.S. Department of State that oversees U.S. involvement in international arms-control negotiations and the Organization for the Prohibition of Chemical Weapons. Its primary responsibility is to monitor developments related to arms control and weapons development.

• The Bureau of Arms Control is responsible for negotiating treaties with other countries to limit the number of nuclear weapons in the world.
• The Bureau of Arms Control also monitors the development of new weapons technology to ensure that it complies with international agreements.

These examples illustrate how the Bureau of Arms Control works to promote international peace and security by limiting the proliferation of weapons of mass destruction. By negotiating treaties and monitoring weapons development, the Bureau helps to prevent the spread of dangerous weapons and reduce the risk of conflict between nations.