The departure of Homeland Security Secretary Janet Napolitano marks the end of the third era at the Department of Homeland Security. Among the more interesting parts of her tenure were:

Travel facilitation became a goal, not a problem: Working within the President’s commitment to grow international travel, the Secretary presided over significant increases in international visitation after the economic slump in 2008-09, in part because of smart travel policies begun during the Bush Administration (Visa Waiver expansion, Global Entry launch) that were expanded and prioritized. The increases were also in part due to new initiatives like tackling problematic visa wait times and the launch of Brand USA. The increases in travel, and resulting economic activity, are all the more impressive since CBP Field Operations and TSA’s budgets were flat during this time period and both agencies had to learn to do more with less.

Managing the immigration enforcement machine: The massive funding buildup at CBP’s Border Patrol and infrastructure accounts and at ICE during the past seven years or so resulted in a much more robust immigration enforcement capability than INS or DHS had ever deployed. However, the President’s preferred immigration policy of legalization has made use of the enforcement tools an inherent contradiction. The Administration has struggled to find a middle ground by emphasizing enforcement against criminal aliens and implementing its own version of the DREAM Act. The fact that former ICE Director John Morton caught as much heat from the left for enforcing the law as from the right for ignoring it demonstrates the difficulty Secretary Napolitano had to manage.

TSA grows up: After two misfires on TSA nominees, DHS found a star performer in TSA Administrator John Pistole, who combined impeccable law enforcement credentials from the FBI with an understanding that TSA was on an unsustainable screening model of treating every passenger like a terrorist. With programs like Pre-Check, Pistole not only improved TSA’s performance but also demonstrated to a skeptical public that TSA does not have to be the laughing stock of late night comedians.

Unlike the Ridge and Chertoff eras, where counterterrorism itself was a policy priority for the Bush Administration, Secretary Napolitano had a boss whose priorities lay elsewhere. You can almost imagine the directive that DHS not create any controversies that would distract from economic and domestic issues.

By preparing DHS to implement immigration reform, improving the face DHS presented to the world, and managing a tough set of responsibilities without massive budget increases, Secretary Napolitano leaves DHS to her successor (Thad Allen? Ray Kelly?) in a different but equally as solid a position as what she inherited four years ago.