H

omeland Security Secretary Janet Napolitano, who led the burgeoning Department of Homeland Security through a host of policy changes in the era after the Sept. 11, 2001 attacks on the U.S., is resigning to head the University of California system.

Napolitano, just the third person to lead the 10-year-old department, told her senior staff Friday she would be leaving to become the president of the University of California system.

The university also announced Napolitano's nomination to be the 20th president of the statewide system. A former Arizona governor and attorney general, Napolitano was appointed by President Barack Obama in 2008.

She had led the department through a series of policy changes with respect to protecting the public safety, including a focus on enforcing immigration laws