It could happen here.
It could happen anywhere.
Any day, at any American ballpark, arena, stadium or finish line, a terrorist or random lunatic could kill us or our loved ones. That has always been true, which became clear as blood on cobblestones on Monday, when bombs killed and maimed people at the Boston Marathon on Patriots' Day in a great American city.
Shrapnel packed into pressure cookers brought sports into the modern world, a world that lives under the daily threat of terrorism.
The good people in Boston on Monday have already proved that those attending sports events will react the way the rest of the modern world has, whether after a bombing at a sidewalk cafe in Tel Aviv or a thwarted gas attack on the tube in London. People learn, as the Brits say, to keep calm and carry on.
There is no other option if you are an American. To live in an open society is to embrace risk. There is no security system that can guarantee safety. From Monday forward, every person at a sports event will have reason to proceed with a heightened sense of awareness, a suspicion of the discarded backpack or a long overcoat on a warm day.
There is a difference, though, between awareness and fear. The people in Boston proved that when they had the most to fear.
Whatever life-imitating entity was responsible for the bombings in Boston wanted to see people running. That wish was fulfilled.