In the summer of 1942, just nine months after the Japanese attack on Pearl Harbor, Ernest "Ernie" L. Kernen graduated from Good Shepherd Catholic School.

That fall, the Frankfort, Ky., native headed to St. Joseph's College.

Yet the world war raged on.

And so, in 1943, Ernie joined the U.S. Marine Corps and deployed to the Pacific theater. There, he joined the 2nd battalion, 22nd Marine Regiment and quickly became best friends with another Irish-American Marine.

Ernest Kernen joined the U.S. Marine Corps in 1943. Flag raising ceremony, Guam. (Photo credits: Kernen family and Damien Barer)

My grandfather, Jim Rogan.

It was a short friendship.

On July 29, 1944, 73 years ago on Saturday, Pfc. Ernest Kernen was killed in action on Guam.

Even today, Ernie's death brings great sadness to Jim, now 92 years old. He describes Ernie as "a really great guy" of good humor and great decency. And Jim vividly remembers Ernie's death.

As their platoon attempted to clear a cave of Japanese soldiers, a Japanese sniper shot Ernie through the chest. Not even 21, he died 7,650 miles from his Frankfort home.

In a letter to Ernie's parents (kindly provided to me by his family), Ernie and Jim's platoon commander, Lt. Tom Jones, offered some context to Ernie's death.

Such was the courage of one and many young Americans.

Still, the fight had to go on. Jim and the 2nd Battalion continued their Pacific tour.

In the spring of 1945, and just prior to the assault on Okinawa, Jim was interviewed for the radio. His hardened voice proved he knew what was coming. At Okinawa, 2nd Battalion suffered a 75 percent casualty rate, with 478 wounded and 127 killed.

Those 127 deserve more than our remembrance. They deserve recognition for battles won.

Again, Ernie proves why.

Just days after Ernie's death, the Battle of Guam was won and our flag raised at the ruins of Guam's Marine barracks. Jones noted that the barracks were "not much over 500 yards from where Ernie was hit." Recording the ceremony, a cameraman, Damien Barer wished "that some of us who hadn't come this far had lived to see this scene ... the reconquest of Guam."

Ernie helped save the world from tyranny.

But he did more than that. He drove his comrades forwards. As Jones explained to Ernie's parents, "The others — we others shall try to carry on and see this thing through as best we can, in the tradition of those Marines who have gone before us these many years, these many battles since 1775 — yes, Mr. Kernen, we shall try to carry on in the tradition of Ernie, your son."

Ernie's tradition is an immortal one.

It is the tradition of Tripoli, Guam, Okinawa, Anbar, Helmand, and many other battlefields from history. And of streets in heaven, guarded by United States Marines.

Semper Fidelis, friend.