At midnight on Friday, September 6, Janet Napolitano can stop worrying about early morning phone calls and the latest terror threats.
After four and a half years as secretary of the Department of Homeland Security - longer than either of her two predecessors - she steps down.
"I will be leaving that to my successor, that's for sure. It's challenging, it's very rewarding. Because the things you do really impact human lives," she said in an interview Thursday at the department's headquarters in Washington.
Starting Saturday, DHS will be led by Deputy Secretary Rand Beers. President Obama has yet to announce a nominee to succeed Napolitano, who came to the position after six years as governor of Arizona.
She leaving to take on a new responsibility, leading the sprawling University of California system.
While preventing terror attacks is job one for Homeland Security, she also led the responses to more than 300 natural disasters, including Hurricane Sandy and a string of deadly tornadoes in the South and Midwest.
She also eliminated the often-ridiculed color coded threat system and, most controversially, introduced body scanners and pat downs as part of airport security.
Yet al-Qaeda's relentless quest to attack U.S. airliners, she said, remains one of the nation's top terror threats. "We've seen it repeatedly in my time as secretary."
Among the most serious plots:
- The attempted bombing of a Detroit-bound plane during Christmas of 2009 by Umar Abdulmutallab, the "Underwear bomber"
- A 2010 effort by terrorists in Yemen to set off explosives hidden in printer cartridges sent to the U.S. as air cargo
- A plot interrupted last year to conceal explosives inside a suicide bomber's body
For al-Qaeda, Napolitano said, targeting U.S. aviation "is kind of the gold standard, because of the successful terror attack on 9/11."
As for increased airline passenger security, she said people have grown more accustomed to it.
"We've moved away from treating all travelers identically. Children twelve years and under can leave their shoes on. If you're older, you don't have to take off your belt or your shoes."
By the end of the year, the Transportation Security Administration plans to add its Pre-Check program for trusted travelers to 100 more U.S. airports.
"We've gone from zero a couple of years ago to virtually uniform coverage by Pre-Check across the country in a very short period of time," Napolitano said.
But one desired change, she said, one also pushed by her predecessor, Michael Chertoff, remains elusive -- lifting the restriction against carrying on liquid containers bigger than three ounces.
"I think we're all stuck with small bottles of shampoo. We are concerned about the use of liquids as explosive devices on planes. It's something our science and technology directorate is working on: Can we develop better screening technology that will allow us to enable people with larger liquid containers to get on planes?"
Earlier this year, Napolitano reversed a highly publicized plan by TSA to allow passengers to begin carrying onboard small pocket knives, hockey or Lacrosse sticks, pool cues, ski poles, and up to two golf clubs.
"There was a public reaction. People like the flight attendants who work in aircraft, they were against it. And we listened and said, okay, we won't make that adjustment. I can't predict if it will ever come back, but we're always working to improve passenger safety."
Napolitano said her biggest disappointment has been the failure of Congress to pass legislation making changes in the US immigration system, though she holds out hope a bill now pending will pass the House, as it did the Senate. Opponents have insisted on more security at the border.
"The border security argument, to me, created the image that somehow we haven't done anything at the border and it's simply loosey-goosey down there. Exactly the opposite is true. Crime and illegal immigration are at 40-year lows."
Illegal immigration persists, she said, because of the demand for illegal labor in the US and the length of time an applicant must wait to enter the country legally.
"Deal with employers who continue to create the demand for illegal labor. Give us the tools to do that and fix the visa system so that you don't continue to educate the next generation of PhD's in engineering and science and then send them away from the United States."
Napolitano will put all that behind her to become, at age 55, the first female president in the 145-year history of the University of California, overseeing ten campuses and five medical centers.
Asked if four and a half years is about as long as anyone could stand the pressure of leading the Department of Homeland Security, she said, "I didn't have as many gray hairs when I started, it's safe to say."
By Pete Williams, Justice Correspondent, NBC News