Our best defense against such threats remains a risk-based, layered security approach that utilizes a range of measures, both seen and unseen, including law enforcement, advanced technology, intelligence, watch-list checks and international collaboration. --Big Sis Napolitano
Of course, the Muslim terrorist who tried the Detroit attack was INBOUND to the US.
And a "risk-based system" worthy of the name would run its extra screens on the usual suspects: male Muslims, usually of Middle-Eastern origin/descent, with one-way cash-paid tickets.
But I suppose that's a quibble.
In fact, the DHS, FBI, and CIA have failed to name the names, here and abroad, so now grannies, 3-year-old girls, and Caucasian pheasant-hunters are subject to "risk-based" inspections which are likely to be violations of the 4th Amendment.
Maybe the airlines need less traffic.