For the four Guerin brothers, "semper fidelis" goes beyond the Marine Corps.
It's a family affair.
Ever since the Vietnam War, the "always faithful" motto has been an extension of their loyalty to each other and their willingness to serve together in the military when the anti-war movement was gaining momentum and the draft weighed heavily on their decisions.
"Do your job. Always be there. If you can't do it, don't go."
That's the philosophy that Mike Guerin, the oldest of the four, had 40 years ago and offers today as advice for Marines like him who are caught in the middle of an unpopular war in Iraq.
"If my country needs me, I'm there. It doesn't bother me one little bit," he said.
The Guerins came to Las Vegas in 1963 from Kingman, Ariz. Mike, now 60, graduated from Rancho High School in 1965 and joined the Marines a year later.
"It was something I enjoyed. I wanted to be a Marine," Mike Guerin said.
As an F-4 Phantom jet engine mechanic, he was sent to DaNang in central Vietnam, then to Japan, and then back to Vietnam, at Chu Lai. There, pulling guard duty, he was constantly badgered by mortar and rifle fire that "scared the daylights out of you."
Before he rotated back to the United States in January 1968, Mike found out that his brother, Bob, had joined the Marines and that the younger, twin Guerins, Ernie and Eddie, were contemplating the same.
Faced with the draft, Bob said, "I figured if I was going to go, I'd go with the best."
In fact, his draft notice came a month after he had enlisted in October 1968, about the same time that Mike had returned from overseas.
After training at Camp Pendleton, Calif., Bob was sent to the northern sector of South Vietnam with the 3rd Marine Division.
"We could see the (North) Vietnamese flags from where I was," he said, describing the location as south of the demilitarized zone.
For much of the seven months he was there, he conducted combat operations in the Asha and Khe Sanh valleys and along the Ho Chi Minh trail.
For 30 days, he was assigned to recover bodies from listening posts and where reconnaissance teams had been attacked.
"We were there to do a job, and I wasn't afraid of dying," said Bob, 58, whose son, Anthony, served in the Marine Corps in the 1990s.
"In Khe Sanh Valley, I had a bullet hit right above my head. It hit a tree and the bark came off. It didn't faze me. We just went on."
In 1969, his unit was the first of the Marines to be pulled out of Vietnam.
"I felt I was fighting to keep the United States in a free world," Bob said. "If I wasn't fighting for our rights, then eventually communism would come to the United States, and that would disrupt our freedom and way of life."
Several months before Bob left Vietnam, Eddie joined the Marines to be an environmental systems mechanic for attack jets.
"At that time, the chances of coming back were better if you were a Marine," Eddie said. "I felt you trained better in the Marines."
He didn't go to Vietnam, nor did he want to. Instead, he cruised the Mediterranean Sea on the USS Independence, returning in early 1971. He was discharged in May 1973 after his squadron endured the cold climate of Norway in a NATO exercise the previous year.
Eddie would later lose his lower left leg to diabetes.
In the meantime, Ernie, now 56, had followed his twin brother's footsteps, joining the Marines in March 1971.
"I had gotten my draft notice. The following day I was at the recruiting depot," he said. "It was a pride thing I wanted to do for my parents."
He noted that he and Bob were stationed together that year for a short time at Camp Pendleton, "so I had a big brother watching over me."
At Camp Pendleton, Ernie developed an ear infection that left scar tissue, resulting in his medical discharge in December 1971 after serving only eight months.
Vietnam "was a big old political war like Iraq is right now," said Ernie, whose son, Eric, served as a Marine in the early 1990s.
Eddie said he doesn't think the war in Iraq can be won, even though U.S. soldiers, Marines, sailors and airmen are fighting hard and are proud of what they're doing.
For a democracy to work, he said, "You've got to have people on your side ... and I don't think it's there. What do these people really want?
"They got to vote for the first time in what, 20 years? If they want it, they're going to have to fight themselves for it. What is it? It's a religious war. They've been fighting it for centuries."
Contact reporter Keith Rogers at email@example.com or (702) 383-0308.