But for the 28-year-old veteran from Logan, it was a journey more personal than he'd ever admitted.
Even to himself.
He had always been a dove, albeit one in Army fatigues.
So as his nation lurched toward war in Iraq, Marshall Thompson was wary.
The Logan soldier had joined the Army Reserves, enlisting as a journalist, upon returning from a church mission in Europe during which he felt immense appreciation for his country. A member of The Church of Jesus Christ of Latter-day Saints, Thompson had been raised to believe in the justness of military service.
He understood his church's scriptures to permit war - as a last resort. The son of a politician, Thompson believed his nation's leaders shared his values.
But as the Iraq invasion approached, Thompson concluded he had been wrong. As an invasion-sized legion of U.S. troops moved into Kuwait, he joined protesters in Logan to demonstrate against the attack. In doing so, he found it was not just political leaders who wanted to go to war.
"We were met by so many counter-protesters," Thompson said. "And they were so angry. The police had to come and stand between us, to protect us."
As the Army called him into active service, Thompson couldn't even convince his own father - then Logan's mayor - that war was a wrong course.
Leaving his new wife - pregnant with their first child - was tough enough. Doing so without his father's understanding was dispiriting.
"It broke my heart when we didn't see eye to eye," Thompson said.
Coming home: Stationed on a large, often-attacked base in northern Iraq, the Army propagandist traveled all over Iraq on orders to seek uplifting stories about fellow troops. Yet Thompson's experiences only further confirmed his fears.
Among U.S. troops he found low morale, brutal tactics and a dehumanizing distance from the people whose country they occupied. Among Iraqis he found anger, fear and distrust of the American occupation.
His superiors allowed him to write about none of those things.
"We wrote in code," Thompson said. "Like, when we would write, 'This soldier has overcome many obstacles', it meant he pretty much complained about his job during the entire interview."
He returned home on July 24 - Pioneer Day in Utah. The blasts of exploding fireworks left him anxious and jumpy.
In Utah, where polls indicate support for the Iraq war runs higher than in any other state, Thompson found many who wanted to hear the kind of news he had been assigned to find in Iraq.
"I felt so alienated," he said. "What people wanted to hear was not what I was able to tell them."
Before returning home, ThompĀson and his wife, Kristen, discussed how they could help make the case for a withdrawal of U.S. troops. A few weeks after his return, they decided: From Idaho to Arizona, he would walk across the "reddest" state in the nation. He could do it in a month - roughly a day of walking for every 100 service members killed in the war.
The stunt, as Thompson called it on his Web site - www.soldierspeace.com - had its intended effect: Media attention drove thousands to his site before he had taken a single step.
The journey began early on the morning of Oct. 2. Approaching Logan that afternoon, Thompson braced himself for a spiteful response, akin to what he had tasted during the prewar protest.
Instead, more than 150 people gathered to walk by his side. Among the ranks was Thompson's father - who in the months since his son's return had come to the conclusion that the war in Iraq needed to end.
Over the next month, Doug Thompson would spend many days walking with his boy.
"It was as if I was finally home," Marshall Thompson said.
Support and sorrow: Thompson logged 25 miles in his first day. Brutally sore the following morning, he found encouragement in the companionship of a Vietnam vet from Oregon, who had learned of the protest on the radio.
Doug Firstbrook hadn't planned on making the entire trek. But he saw something in Thompson that was painfully familiar.
"We had similar jobs," said Firstbrook, a former Army journalist. "We both saw, firsthand, how information was manipulated and suppressed by the military. We both had a part in it."
The gray-bearded carpenter decided to stay by Thompson's side, logging an average of 20 miles each day through wind and rain and snow.
In Salt Lake City - a blue dot on a very red map - about 100 people turned out to walk. But the real surprise came as he marched into Provo, past Ephraim, and through Richfield. In every town he had written off as "too red" for his message, Thompson found flocks who agreed.
But as he moved farther south, the initial euphoria of his successes faded away. Greater distances separated smaller towns. And even with Firstbrook and sporadic others at his side, the miles were quiet and lonely.
Then, two weeks in, Kristen called with some frightening news: Their infant daughter, Eliza, had a lump on her neck. Doctors feared cancer, maybe leukemia.
Sitting alone in a hotel in Panguich, Thompson was awash in doubt.
"I thought: Is it worth it? I mean, it was just a stunt," he said. "We were having a family crisis and here I was in the middle of Nowhere, Utah - walking for peace."
But Kristen turned down her husband's offer to return home.
"We'll be OK," she told him. "We made it through a year with you in Iraq. We'll get through this."
For Kristen, the walk had become more than a stunt. With each passing mile, she could see her husband was changing. And she wanted him to continue.
Dealing with the dreams: Marshall Thompson wasn't unrecognizable to his wife when he returned home from Iraq - but he was different.
By his own admission, he angered easier and had less patience - symptoms of post-traumatic stress disorder. He slept fitfully. And, on at least one occasion, Kristen had to wake her husband from a dream so real and terrifying that he was sobbing in his sleep.
But as he walked, connecting with fellow veterans, his father, and others "who love and accept me just for the fact that I came home alive," Thompson felt his symptoms melting away.
"Every symptom of PTSD, and especially the anger, just disappeared completely," he said. "For the first time since coming home I felt very in control and very normal."
And with that came the ability to deal with things once hidden.
There is a lot of time to think in 500 miles. And as he walked, Thompson's thoughts turned often to a night he spent on a dark highway near Balad, Iraq.
His truck, separated from its convoy, was waiting on the side of the road when a civilian vehicle pulled up and flashed its lights. The driver waited a moment, then flashed again.
On a night which began with small arms fire and included several close calls with roadside bombs, the commander of Thompson's truck was nervous the civilian driver might be signaling an attack. He ordered Thompson to point his rifle at the driver of the car.
"He said, 'If he flashes his lights again, kill him.' "
For three hours, Thompson trained his sights on the driver's head. Seated on the gravel side of Utah's Highway 89, a day's walk south of Hatch, last week, Thompson cried at the memory.
"It's so horrible, because you have this guy - can you imagine how terrified he must have been?"
Implied in the truck commander's order was a moral decision difficult for Thompson to accept: That the life of the car's driver - most likely a civilian in the wrong place at the wrong time - was worth less than his own.
And yet Thompson knew how he would have reacted had the lights flashed again. He had been given three hours to think it over and he was certain.
"I would have killed him," he sobbed. "Just a man. An innocent person. How can you possibly square that with what you believe?"
A soldier's peace: Doctors plan to perform a biopsy on the lump on Eliza Thompson's neck later this week. Because she's shown no other signs of sickness, they are hopeful it is not cancerous, but the little girl's father still worries.
He wants to be near his daughter. He misses his wife. He pines for his bed. His feet are tired and, even as he moves farther south, the days are growing darker, colder. And so the soldier is eager for his walk to end as planned on Wednesday, even if the journey has helped him in ways he couldn't have comprehended.
When he began, on the Idaho border, Thompson called his trek a stunt. But now, as he approaches Arizona, he's more apt to call it penance.
"I think that maybe I've known that from the beginning," he said. "But I didn't want to say it. When you say something like that, I think, it's hard for people to understand."
And yet understanding, he has come to realize, is not so hard to find.
Even for a dove in Army fatigues. Even in Utah.