The Lesson of Boston - NYTimes.com IF only it were as simple as the drones coming home to roost. That would be comforting somehow. In giving us a tidy cause, it would give us a clear remedy: rain less death in distant lands, and worry less about death in our own. If only it could all be chalked up to immigration leniency or an F.B.I. blunder. We could get tougher on both fronts, turning a warier eye toward anyone aspiring to come here, cracking the whip over at Quantico. And maybe then we could vanquish the worry that blooms darkly inside many of us when we visit a thronged landmark or attend the kind of richly symbolic event, like the Boston Marathon, whose violent disruption carries all the extra horror its disrupters intend. Last week was one of theories, of hobbyhorses, of political complaints and agendas being hitched like so many train cars to what happened on that brutal afternoon in Boston. The assailants" radicalization proved that we must scale back our military campaigns and take a humbler posture in the world. The assailants" firepower (overstated, it turns out) made a case for gun control. We had to be more expansive in our embrace of Muslims, who become agents of destruction because they're targets of suspicion. We had to slough off political correctness and patrol mosques. Oh, the pitfalls of the amnesty our country grants and the big heart it opens to determined pilgrims from the third world! Oh, the peril of all our aimless, alienated young men! Are there many other kinds? But these broad-brush diagnoses, many of them conveniently tethered to a proposed solution, weren't entirely or even ultimately about policy, sociology or anything so concrete. They were about something much more nebulous and much less easily mastered. They were about fear. And they were about the ardent, persistent, poignant hunger to believe that in a society of free information and free movement and clashing ideologies and gaudy dreams that don't come true - in other words, in this splendid but difficult experiment known as the United States of America - we can somehow prevent disaster, somehow inoculate ourselves. With a sufficiently probing analysis of a suspect's Twitter feed, with the designation of a broken 19-year-old as an enemy combatant, we could unravel the riddle, then adjust to and obey the truths at its core. On NBC's "Meet the Press" last weekend, Doris Kearns Goodwin described a celebration that erupted in the bar where she happened to have been when it was reported that the younger of the brothers Tsarnaev was captured: "Everybody was just screaming, "Thank God we got him alive," because they want the answer to the question, why?" And over the days that followed they got - we got - many answers. We learned that Dzhokhar Tsarnaev was easily swayed by Tamerlan Tsarnaev, 26, a sibling dynamic of an utterly routine stripe. We learned that the Internet and social media sped one or both of them to wicked influences and let them steep in anger and twisted thoughts, the way the Internet and social media let anyone concentrate on a specific obsession, a single cluster of emotions. We learned that they'd plucked bomb-making instructions from the Web, in much the way someone else might retrieve a guacamole recipe. All in all we learned at least as much to amplify our anxieties as to quiet them, because the Tsarnaevs were seemingly inconspicuous, haphazard terrorists, and because the picture that emerged didn't really yield a set of instructions for staving off the manner of mayhem they allegedly engineered from occurring again. It suggested how easily this can happen in a land of liberty, governed by a compact of trust. THE brothers had ample reason to love America. More reason, it would seem, than to hate it. When their family, of Chechen heritage, asked for refuge, America said yes. It extended them opportunities, gave them hope. Dzhokhar went to the same high school that Ben Affleck and Matt Damon had attended, and when he graduated, the city of Cambridge, Mass., awarded him a $2,500 scholarship for his future studies. But college didn't go well for him, just as Tamerlan's boxing career - he'd once aspired to represent this country in the Olympics - didn't pan out. And the big promises of our country no doubt make its disappointments all the more crushing. But the big promises also make us who we are. The brothers apparently objected to our interventions in Iraq and Afghanistan. But do we know that they wouldn't have had some other plaint, some other prompt, if those interventions had never occurred? They postdated 9/11, whose authors had a brimming portfolio of alternate grievances. Where there's a capacity for fury, justifications aren't hard to come by. Timothy McVeigh, the Oklahoma City bomber, cited the government's raid on the Branch Davidians in Waco, Tex., as one of his prods. He was neither Muslim nor immigrant, just unhinged, a characterization that also fits Anders Behring Breivik, who blamed Europe's acquiescence to multiculturalism for his killing of 77 people in Norway in 2011. Terrorism isn't a scourge we Americans alone endure, and it's seldom about any one thing, or any two things. Our insistence on patterns and commonalities and some kind of understanding assumes coherence to the massacres, rationality. But the difference between the aimless, alienated young men who do not plant bombs or open fire on unsuspecting crowds - which is the vast majority of them - and those who do is less likely to be some discrete radicalization process that we can diagram and eradicate than a dose, sometimes a heavy one, of pure madness. And there's no easy antidote to that. No amulet against it. There's also a danger built into the American experiment, the very nature of which leaves us exposed. Our rightly cherished diversity can make the challenge of belonging that much steeper. Our good fortune and leadership mean that we'll be not just envied in the world, but also reviled. The F.B.I. averted its gaze from the older Tsarnaev brother after it couldn't find any conclusive alarms because that's what the government is supposed to do, absent better information. We don't want it to go too far in spying on us. That means it will fail to notice things. While we can and will figure out small ways to be safer, we have to come to terms with the reality that we'll never be safe, not with unrestricted travel through cyberspace. Not with the Second Amendment. Not with the privacy we expect. Not with the liberty we demand. That's the bargain we've made. It's imperfect, but it's the right one.