While living in Marietta, Ga., I attended a memorial service for U.S. Marine Lance Cpl. Skip Wells, who was murdered during the July 2015 terrorist attack in Chattanooga, Tenn. In the weeks after he was laid to rest, one of my daughter’s preschool teachers told me that she had cared for Skip when he was a toddler. My family and I have since moved to Florida, and already there has been a terrorist attack in our new state. Early Sunday morning in Orlando, a terrorist dialed 911 and pledged his allegiance to ISIS while he was butchering innocent Americans.

Orlando joins a growing list of American cities to be targeted by radical Islamic terrorists since 9/11, which includes Chattanooga, San Bernardino, Boston and Fort Hood. Between these attacks and the nation’s ongoing military conflicts, most Americans probably know someone whose life has been shattered by terrorism.

Some are too young to remember the horrors of 9/11, but after numerous attacks on U.S. soil in the years since, no one has an excuse for diminishing the terror threat. Unless we want our kids to grow up in a world where nightclubs, businesses, marathons and military bases are considered likely targets, we must collectively realize that the struggle against ISIS in particular, and radical Islam in general, is World War III.

Last week, America marked the 72-year anniversary of our military heroes storming the beaches of Normandy on D-Day. While some didn’t initially understand the threat posed by Nazi Germany, fascist Italy and imperial Japan, Americans came together after the attack on Pearl Harbor. No matter the cost, the Greatest Generation resolved to defeat evil so their children and grandchildren could grow up in a safer world.

Imagine if after the carnage in Hawaii, Americans wasted months or years arguing about whether Pearl Harbor was an attack by Japan or just a tragic, isolated incident. Imagine if Americans had surrendered instead of enduring the enormous casualties suffered at Normandy, Iwo Jima, Guadalcanal or the Battle of the Bulge.

Granted, if either of these scenarios had come to fruition, we wouldn’t be living under the constant threat of terrorism. Instead, we would be living in the dark world portrayed in Amazon’s The Man in the High Castle, where New York skyscrapers are decorated with swastikas and the streets of San Francisco are patrolled by Japanese troops.

Some might say that I’m being an alarmist by comparing the conflict with ISIS to World War II. Yet as the Islamic State’s army of darkness keeps murdering innocent American men, women and children with bullets and bombs, ask yourself one question: What would these fanatics do with nuclear or biological weapons?

Does this generation of young men and women have the will to fight ISIS? After attending the funerals of fallen heroes like Lance Cpl. Skip Wells and visiting Walter Reed to speak with severely wounded veterans, I believe the answer is – unquestionably – yes. Ask these volunteer warriors to save the world from radical Islamic terrorism, and that’s exactly what they’ll do.

The time to confront evil is now. If Americans don’t come together to destroy ISIS and its fellow travelers, you or a loved one could be their next victim.

Tom Sileo is co-author of Fire in My Eyes and Brothers Forever, and recipient of the Marine Corps Heritage Foundation’s 2016 General Oliver P. Smith Award for distinguished reporting. Follow him on Twitter.