Detachment
Midway through the Vietnam War, many American soldiers felt a level of detachment stemming from a general lack of understanding as to why they were there. Others performed unadulterated acts of violence simply because they thought they were fulfilling a duty. Either way, the patriotic "war hero" figure that emerged after World War II was fully shattered for many young soldiers, and Coppola expresses this in several instances in Apocalypse Now. Kilgore has made a sport out of killing, eviscerating an entire village in order to move the PBR to the mouth of the Nung River. He celebrates the drama of killing by playing Ride of the Valkyries on a loudspeaker to signal the arrival of his Air Cavalry. On a smaller scale, Mr. Clean opens fire on a sampan of innocent Vietnamese people before Chef is able to discern if they are dangerous or not. Throughout, the soldiers who perpetrate feats of grotesque violence do not seem to process the full weight of their actions.
Desperation
There are many levels of desperation in Apocalypse Now. From the opening scene, it is evident that Willard is fighting his inner demons, and has returned to Saigon because he does not recognize his pre-Vietnam life anymore. The sailors on the PBR are desperate to finish their duty and return home alive, especially Chef. This is clearly a common feeling amongst the American troops - soldiers cling to the landing skids of the Playboy Bunnies' helicopter, and when the PBR pulls into the murky scene around the Do Lung Bridge, soldiers actually jump into the water for a chance at a ride home. These characters are in contrast with those who are in Vietnam with an expressed mission: Willard, Kurtz, and Kilgore. The atmosphere of desperation helps Coppola's achieve his desire to depict the Vietnam War as it was for the people on the ground.
Exploitation
Exploitation existed on both sides of the conflict in Vietnam - on the war front and at home. Both Kurtz and Willard speak about the lies surrounding the American presence there. Kurtz is, in effect, a representation of the ugly truth: millions of innocents, both Americans and Vietnamese, are dying as a result of the American political agenda. We see this in Kilgore's air raid, in which the Air Cavalry takes out an entire village for the purpose of moving the PBR upriver. Meanwhile, Willard comments that the American tactic is to "cut [The Vietnamese] in half with machine gun and give them a band-aid." A big part of the Vietnam War narrative is the way that the American media kept trying to sell it to the public, praising the war effort day after day. Ultimately, the war was political maneuvering, plain and simple, and has created a stain on American history.
Journey
Like Joseph Conrad's novel on which the film is loosely based, Coppola structures the narrative of Apocalypse Now as a journey. Willard arrives in Saigon with the goal of being assigned to a new mission, because after his first tour of Vietnam, he no longer fits into his civilian life. Therefore, his journey to find Kurtz is both literal and metaphorical - a journey into the jungle and into himself. On the way, he was forced to address the darkest corners of his soul. The only way Willard can reject Kurtz is to see himself in Kurtz. Kurtz, meanwhile, knows his time has come but gives Willard a new mission: to go back to America and tell Kurtz's son the truth about his father. In this way, Willard's first mission is to uncover the dirty truths behind the Vietnam War, and his future journey is to reveal them to the people at home.
Throughout the production, Francis Ford Coppola was not unlike his protagonist. The director's wife, Eleanor, wrote in her journal that she saw her husband going through his own transformative experience during production. Like Willard, Coppola was taking his crew deep into the heart of the jungle, and had to face enormous difficulties and emotional issues in order to tell the story he wanted to tell while keeping his life - and his sanity - in tact.
Accountability
One of the lingering controversies surrounding the Vietnam War is that of accountability. In one particularly brutal example, the My Lai Massacre (where 100 American Soldiers massacred over 500 innocent Vietnamese civilians over the course of 4 hours), resulted in very little judiciary action. Apocalypse Now, however, examines the impact of personal accountability. Although every soldier in the film has to commit some level of atrocity in the name of patriotism, these brutal acts eat away at a man's humanity. Kurtz, meanwhile, has seen such horrors that he can no longer climb out of his own darkness, but after their encounter, Willard learns to accept that darkness inside himself and chooses to suppress it. As he walks out of the temple after killing Kurtz, he could easily step into Kurtz's position, but he chooses not to. He holds himself accountable, even if his followers would not.
Innocence
The most controversial aspect of the Vietnam War was the number of innocent people who suffered on both sides. Coppola depicts shattered innocence in a number of ways throughout Apocalypse Now. When Willard boards the PBR, he describes his crew as "rock and rollers with one foot in their graves," implying that they are fun-loving young people naive to the brutality that lies ahead. During the sampan massacre, Coppola makes this point with heavy symbolism - Mr. Clean shoots everyone on the boat after a woman tries too hard to protect the contents of a woven basket. After the other passengers are dead, Chef discovers that there is a puppy in the basket, which Lance adopts and keeps close to him. After young Mr. Clean is killed, the puppy disappears. In the film, Lance remains a figure of childlike innocence. He keeps the puppy close to his chest to protect it from gunfire. He gives Chief a respectful burial at sea. When they arrive at Kurtz's compound, he shoots down a corpse hanging from a tree. He holds onto whatever shreds of humanity he can find in the dark, menacing jungle.
Insanity
The question of insanity underlies the driving force of Willard's entire mission against Kurtz. When Corman briefs Willard, he offers his own practical explanation of Kurtz's crimes: "Every man has got a breaking point. You and I have. Walter Kurtz has reached his. And very obviously, he has gone insane." While Corman alleges that Kurtz's paranoia led to him murdering four South Vietnamese intelligence agents, Kurtz writes in his letters home that it's the charges against him that are insane. While Kurtz has snapped, he is very lucid about many of his decisions - and that is terrifying to the men who are supposed to be controlling him. On the other side, Kilgore is similarly over the top. He actually likes to have a soundtrack to his air raids, and makes his soldiers go surfing in the middle of gunfire. Yet, Kilgore is on one side of the war, a hero, and Kurtz is on the other, a menace. Kurtz, meanwhile, defines whatever has happened to him as the ultimate clarity, and he sees men like Willard as lacking agency: "errand boy[s] sent by grocery clerks to collect the bill." Insanity on the battlefield is a common trope used in works of art depicting life during wartime (The Red Badge of Courage, Catch-22, Slaughterhouse Five, etc.), but Coppola's exploration of blurred morality is appropriately visceral as the Vietnam War itself was muddied in purpose.
