On the morning of Sept. 11, 2001, Jackie and Robert Norton, a retired couple from Lubec, boarded American Airlines Flight 11 to visit California for a family wedding. Carol Flyzik, whose family lives in Parsonsfield, was on the same flight for a business trip. James Roux, a Portland lawyer, was aboard United Flight 175 for the first leg of his trip to Thailand.

Stephen Ward, who attended Gorham High School and the University of Maine, was settled into his 101st-floor office of the World Trade Center in New York. Cmdr. Robert Schlegel, who graduated from high school in Gray, where his mother lives, was at work at his office in the Pentagon.

Then the planes became weapons, boring into the twin towers, plowing into the Pentagon, and killing each of those people that day. Our world changed instantly, and it kept on changing, until nothing felt quite the same. And as the Maine families grieved, desperate to make sense of their inexplicable loss, we waged a war that continues to lead us into unfamiliar territory.

We went to Afghanistan and routed a murderous regime and the terrorists it harbored. We secured our borders and bridges, fretted over anthrax, and grumbled about the new hassles that greeted us whenever we needed to fly.

We formed the Office of Homeland Security, scrambled to redefine emergency-response services and law-enforcement systems across the country, and hastily assembled the surveillance and communications networks that we prayed would keep us safe from another unthinkable attack.

On Sept. 11, 2002, we reopened our old wounds for a time and then moved on. Soon after, we held our breath as our friends and loved ones marched into Iraq to topple a tyrant.

In the 20 months since that fateful day, our nation has been forced to take protective measures that most of us would have thought inconceivable before. And while we hope never to have to test those new safeguards against large-scale violence, they’ve already worked wonders in a smaller way.

It happened just 10 days ago, in the little northern Maine town of New Sweden, when a gathering of church people drank coffee heavily laced with arsenic. When one man died, and 15 more were hospitalized, two acts of terrorism converged in the most extraordinary fashion. The improvements that hospitals made after 9-11, Maine health officials declared, allowed doctors to treat this extremely rare instance of mass poisoning far more effectively than they could have before.

The post-9-11 changes helped scientists and health workers rapidly identify the poison, administer special new medicines that saved lives, and share information more quickly than was possible in the past. Of the six nurse epidemiologists hired in Maine since the war on terrorism began, the one in Aroostook County immediately began investigating the incident while a new medical toxicologist helped identify the high level of poison in these unlikeliest of victims.

The terrorist attacks that took the lives of those Maine people on 9-11, in other words, had set into motion a chain of events that ultimately saved the lives of several other Maine victims.

There are many names for the uncanny confluence of all human acts. Some call it karma, some destiny or fate. Others might see it as a divine plan, or merely coincidence. But the name doesn’t matter as much as the reminder it offers: That good can often evolve from tragedy, and hope from despair, even when the transformation is hard to recognize.