For more than a century the Boston Marathon has been one of the sporting world's most venerable and revered traditions, carrying on through two world wars, the Great Depression and various other upheavals - so when two bombs exploded at the finish line last year, resulting in three deaths and more than 260 injuries, no one ever doubted that the 26.2-mile foot race would be back today.

Some 36,000 runners will set off from Hopkinton, Mass., and more than a million people are expected to cheer them on all the way to downtown Boston in a show of support for an institution and a city too strong to bow to a terror attack.

Authorities have planned extraordinary security measures to ensure the safety of competitors and spectators. For some that may diminish the festive atmosphere that has been a Boston Marathon hallmark. For instance, jubilant spectators, who used to reach out and offer sliced oranges, cups of water and high-fives to runners, will be kept farther away by fences and extra legions of armed police. Runners will be herded into a heavily guarded "athletes' village" at the start instead of being allowed to roam around before they hit the start line. And unregistered runners, popularly known as "bandits," who regularly have jumped into the race and loped along with those wearing numbers, will be prohibited this year.

These are unfortunate but necessary precautions that reflect a sign of the times.

It may be a poor comparison considering what is now taking place in Russia, but the Winter Olympics in Sochi earlier this year demonstrated that international events can take place safely amid threats of terrorism. If we have to sacrifice a few liberties along the way, so be it.

As if to underscore this atmosphere, Boston police took one man into custody on Boylston Street Tuesday night near the Boston Marathon finish line and blew up two backpacks after the suspect said that he had a rice cooker in one of them.

This was a grim reminder of last year's race, when authorities say two ethnic Chechen brothers set off two bombs in backpacks near the same spot. Tamerlan Tsarnaev, 26, died following a shootout with police days later. Dzhokhar Tsarnaev, 20, has pleaded not guilty to federal charges and is awaiting a trial in which he faces a possible death sentence. Prosecutors say the brothers also killed MIT police Officer Sean Collier.

Though we must remain vigilant against a constant threat of terrorism or nonpolitical actions by deranged individuals, we must also not lose sight of the fact that for many, the Boston Marathon is as popular a tradition as a Thanksgiving Day parade or fireworks on the Fourth of July.

It's a tradition that resonates in southeastern Connecticut, home of two popular champions: Johnny Kelley in 1957 and Amby Burfoot in 1968. Johnny, who was born in New London, taught at Fitch Senior High School in Groton and lived in Mystic, died in 2011 at age 80. Amby, who grew up in Groton Long Point and ran on a high school cross-country team coached by Mr. Kelley, also taught school in Groton before he joined the Peace Corps and then worked as executive editor of Runner's World magazine. After he retired last year Mr. Burfoot moved to Mystic.

He will be running the race again this year with a group of family and friends. He plans to hand out cards along the way thanking spectators for their support, and to wear a shirt that honors the memory of last year's victims.

We applaud such thoughtful gestures that remind us a marathon that so many of us associated solely with the pure joy of athleticism must now also serve as a memorial tribute.

During the buildup to the race over the past several weeks, news reports have focused not just on the horror of last year's explosions but also the resilience of those who lost family members and friends or suffered devastating injuries. All are unified by an unflagging spirit and determination exemplified by the words, "Boston strong."

Vice President Joe Biden, who attended a ceremony in Boston honoring the victims, said it well when he noted that the courage shown by survivors, responders and those who lost loved ones must inspire other Americans dealing with loss and tragedy.

"You have become the face of America's resolve," he said. "America will never, ever, ever stand down. We own the finish line."