A would-be bomber had just tried to blow up a plane on Christmas Day, so we braced for extra security measures as we headed to the airport for a flight from Chicago to Baltimore last Sunday.

Expecting a gantlet of pat-downs, dog sniffs and, who knows, mandatory trou-drops once we got inside, my husband and I decided to check in curbside. The agent asked our names and destination - prompting an exchange of groans over the Ravens' self-destruction in Pittsburgh that day - and soon our bags were on the conveyor belt and we had our boarding passes.

Without ever being asked to show any identification.

Maybe it had been a long day, or a long holiday travel season. Maybe it was the distraction of my charming smile, or the tip my husband proffered, or the agent's going off on a tangent about Ray Lewis.

Whatever, even under a heightened alert, he let his guard down. The armor, for all the added layers, displayed a chink.

Harmlessly in this case, since the most dangerous thing I was packing was a stash of my sister's homemade chocolate turtles, but still unsettling.

I'm all for tighter measures - bring on the full-body scans, already - but let's face it, no amount of stiffer regulations is going to prevent human beings from being human. As in flawed and less than 100 percent vigilant every moment of the day.

And yet, if the news Christmas Day showed us anything - and I'm also thinking of the horrific kidnapping and murder of 11-year-old Sarah Foxwell in Salisbury, and the known child sex offender who has been arrested in her abduction - we flawed and easily distracted individuals are our own first line of defense.

The recriminations come fast and furious after such shocking events: Every disgruntled Muslim should be on a no-fly list; every child sex offender should be jailed for life, if not beyond.

But there is no prison term long enough and no watch list comprehensive enough that can save the Sarahs or the Flight 253s of the world by themselves. Not that we shouldn't keep trying to improve sentencing guidelines or terrorist monitoring procedures, but it seems in both cases, the keys to their prevention could be found right at home.

With Umar Farouk Abdulmutallab, who is accused of trying to bomb the Detroit-bound plane, it sounds like his father actually did the right thing, warning U.S. Embassy officials in November of his son's increasing radicalism. While there are conflicting reports over how specific the father was, the concerns were enough to prompt intelligence officials to investigate the son, but not enough, apparently, to get him onto a watch list.

Everything is much clearer in retrospect than as it's actually unfolding, and so it is as well with Thomas James Leggs Jr., the Salisbury man charged in connection with the kidnapping of Sarah.

At this point, we don't know much about Sarah's guardian, the aunt with whom she lived. We don't know when the aunt learned that Leggs, whom she dated for a while, was a child sex offender.

Still, you have to wonder if the aunt ever Googled this guy while she was hanging around with him - especially since they were close enough for him to know where she hid the spare house key. And once they were kaput, especially if at that point she knew about his prior crimes, why would she not find somewhere else to hide that key, preferably in a less obvious place than a flowerpot on the porch?

We're in an odd place these days, frightened by the prospect of terrorists and molesters and other real-life monsters, and yet also complacent to the point that we've turned the responsibility for our safety over to others. And of course, there are officials whose job it is to protect us - the cops, the feds, those who put people on sex offender registries (as Leggs had been) and no-fly lists (as Abdulmutallab hadn't).

But then there are the rest of us. Maybe the idea of individual vigilance seems quaint, like when kids were encouraged to scan the skies for any approaching enemy planes during World War II.

Instead, after 9/11, we were told to go out and shop. No one has said that lately, and yet it's only when a moment of clarity like Flight 253 occurs that we realize the need for more and constant engagement in the world.

We saw that this past week, when other passengers on the plane and crew members overwhelmed Abdulmuttallab, and thousands of regular people swarmed Salisbury on Christmas Day to search for Sarah.

There is a natural instinct to want to help, to do the right thing, and surely that is something our leaders can find a way to tap into. And not just during a crisis or, sadly, after the fact, when it's too late to help a little girl.