SIOUX CITY | Look back at historical photos and films of World War II.
They're mostly black and white, and, in simple terms, so were the objectives and reasons behind the war.
Stop Nazi and Japanese expansion. Do what it takes to force the other side to surrender.
Vietnam was a war recorded in color film and photos.
Green jungles and military uniforms. Red blood.
The reasons behind the war, the objectives, the orders dictating how it would be fought -- came in all shades. Who exactly are we fighting? How far should we go to win? Should we even be there at all?
Lessons learned from fighting previous wars didn't help much.
And the lessons gained from Vietnam?
Much like the war, they're not quite that clear. Even less so is whether we learned from them.
"What I tell my students is, there is no single book which is capable of presenting the full reality of the Vietnam War," said Greg Guelcher, a Morningside College professor teaching a research seminar on the war this semester. "It's a more complicated war than any in recent history. You should read multiple accounts by people who were there."
For the Journal's 50-day series featuring Vietnam veterans, reporters asked those who slogged through Vietnam's jungles, endured its sweltering heat and survived nighttime rocket attacks what it was like, how they coped and, lastly, what we as a nation learned. Some had no problem answering. Others weren't sure. Many said our nation continues to make the same mistakes made 50 years ago.
Dan Young, veteran, Alta, Iowa: "I'm not sure the nation really learned anything. It seems like we just keep going from one conflict to another and don't really get anything accomplished."
His comment, similar to what reporters heard from many other veterans, illustrates a major lesson from Vietnam, Guelcher said.
"If you're going to war, you need to be very clear about the reason why you're going to war and clear on the definition of victory," he said. "As a historian, I would argue the United States never adequately defined what victory meant. The goals, they never got much past the domino theory and stopping communism."
Many of those who fought in Vietnam would say that was the fault of politicians, not the military. Some wish the politicians had left military leaders alone to plan, fight and win the war.
Larry Locke, veteran, Sioux City: "The military should have run the war, not Washington, D.C. There were times you could have wreaked havoc on the enemy, but you couldn't. ... The rules of engagement, it is stupid. It should be left to commanders, not to politicians. If you want to fight a war, fight it."
A key to fighting any war is knowing the country and its history. Guelcher said it's a lesson the United States could have learned from studying Vietnam's history of repelling one invader after another for the previous 2,000 years.
"If you're going to go in and fight in another country, we need to know about that country, its culture and its people," he said. "We didn't do that in Vietnam. We didn't do it in Iraq and Afghanistan."
Those recent wars in Iraq and Afghanistan drew several comparisons from Vietnam veterans. They're not a perfect parallel, Guelcher said, but veterans see many similarities.
Bob Brodersen, veteran, South Sioux City: "We're running into the same kind of predicament that we were in 40 years ago. We were there to fight the communists, now we're back fighting ISIS (in the Middle East). It's a repeat of where we were in the Vietnam War. Where it ends, who knows?"
What veterans do know is that troops returning home nowadays receive a much warmer welcome from the public. Many told reporters of getting hostile receptions from war protesters when they returned home. Some said they were spit on and never wore their uniforms again.
That has changed.
Craig Wollman, veteran, Sioux City: "As individuals, we've learned to honor our veterans, and we see that a lot in the way the people coming home from the Middle East conflicts since the Desert Storm/Desert Shield thing in '90 have been treated with respect and honor. Most of the Vietnam veterans didn't get that."
It may be one of the lessons that really sank in, said Steve Feimer, a University of South Dakota associate professor of criminal justice who is writing a book titled "Vietnam Veterans: Still Coming Home -- Their Stories in Their Words," a compilation of recollections from 32 Vietnam veterans.
"I think one of the things we learned from Vietnam is how not to treat returning veterans," Feimer said. "They didn't get parades. There wasn't much of an effort to deprogram them. We don't want to treat veterans now the way we treated Vietnam veterans back then."
Vietnam was a perplexing war 50 years ago, one historians still are trying to decipher.
Surely, our nation learned from it.
It shouldn't be surprising that a war that created so much controversy and so many different narratives decades later still leads to uncertainty about just what it taught us.
Have we learned lessons? Yes.
What are those lessons? Each of us may have to decide on our own.
But our responses will be colored by our life's experiences and influences.
Don't expect many black-and-white answers.