How do you know that an event has ripped through the soul of America? When you are at a bar, listening to a close friend choke back tears as she tells you how the man she thought she was going to marry is breaking up with her, while an image flutters across the pub's TV screen. She pauses, wipes her eyes, and says, "Isn't it awful what happened to those students?" The slaughter of 32 innocent people at Virginia Tech University is a case of public tragedy trumping the personal. That sad reality can be glimpsed in a moment with a friend's heartfelt comment or the immediate decision of presidential contender Rudy Giuliani to cancel all political appearances. Or it can be grasped over many hours, as CNN never breaks to another story and other news can be hard to find even on its scrolling textlines. Perhaps more to the point, it is a case of public tragedy becoming personal. Because the shooting in the Blue Ridge mountains that form the sturdy spine of the country's hinterlands frays US nerves at a time when violence has become an unwelcome guest in more and more American homes. On the national scene, the political debate - in the second-term White House, in the newly installed Congress, in the yet-to-start presidential campaign - is dominated by two (though some might say one) overarching life-and-death concerns: the carnage of American soldiers abroad in Iraq (and, to a lesser degree, Afghanistan), and the broader struggle to safeguard the home front in the USA. To the extent that Americans have been lulled into a sense of security - it has, after all, been more than five years since September 11 and there have been no further terrorist attacks on US soil - the Virginia Tech shooting spree shattered it. There has been no suggestion that the gunman was a terrorist. But the ease with which he carried out the cold-blooded murder of 32 innocent people, over a span of hours, with no adequate police response or university emergency management system in place, only highlights the vulnerability of America to further attacks. On some level, it suggests an American failure to internalize the threats it faces sufficiently to have implemented strategies for coping with them. And that lack makes everyone in the country, no matter how far removed from the Blacksburg, Virginia campus some 440 kilometers from Washington, DC, feel insecure. That such an atrocity would occur on a campus only amplifies the fears. "What has happened here reverberated throughout all of higher education, indeed, the world," University Vice President for Student Affairs Zenobia Hikes told the thousands assembled Tuesday at a convocation ceremony held in the school's basketball arena, which US President George W. Bush attended. "We have lost the sense of peace that comes with learning," she said. Indeed, campuses are symbolized by the term "ivory tower," which suggests not just loftiness but impregnability as well. Though security has been increased in recent decades, mainly in response to thefts and rapes, universities remain open to and welcoming of the public. And so America needs to brace for a new argument over academic freedom - in this case freedom of movement in the academic world. It is an argument, often tagged as democracy versus security, that has been carried out with no clear resolution for the past five years. Additionally, the fact that the perpetrator was an immigrant intensifies another simmering debate, this one over Americans' fears about foreigners and how to keep out the truly dangerous among them. And yet, a closer look at what is known so far about Cho Seung Hui suggests that his crime is much more American than foreign. According to media accounts, Cho, 23, came to the US at the age of eight with his parents from South Korea, meaning he spent most of his life in America. He held a green card and was in fact an English major at the university. His crime, while the most deadly shooting rampage in American history, echoes previous attacks at American institutions by crazed gunmen. They have been common enough to spawn a slang term - "going postal" - and serious enough to cause many school districts to erect metal detectors and boost counseling services for distressed students. The most significant of these was the massacre of 13 people at Columbine High School in Colorado almost eight years ago to the day. That incident sparked a politically charged debate about guns, an issue which had already been getting more attention in recent days because of surging murder rates in several American cities. This time, a dozen presidential candidates stand waiting to weigh in. All of this underscores that whatever the external threats America faces, it is the internal one that could be the most dangerous. And that makes the pain of this tragedy very moving and very personal indeed.