Conversation so far:
who does department of homeland security report to
The heads of the executive departments serve at the pleasure of the President.
When was the Department of Homeland Security formed?
The United States Department of Homeland Security was created in November 2002 in response to 9/11 and is the youngest U.S. cabinet department.

Question: What is the purpose of the department?
Self-contained rewrite: What is the purpose of the Department of Homeland Security?