Stephen Rojack has got to be one of the least likable protagonists of all-time. This guy murders his wife in the opening chapter, goes on a series of sexually predatory misadventures, and manipulates every person he meets. On the surface, though, it seems like he has the perfect life, like he has achieved the American Dream… So why does he feel so empty inside?
By all counts, Rojack should be in the prime of his life. As the novel's title suggests, this guy has achieved the American Dream, going from war hero to congressman to a "star of sorts on a television show" with a "notorious reputation" (1.48). It's about as American as apple pie, right? Rojack has a secret, though: The only way he was able to gain "entry to the big league" (1.48) of high society was by marrying a wealthy heiress named Deborah Kelly. As you might imagine, Rojack is pretty ashamed of the fact he hasn't made it on his own merits.
With time, this eats away at him. Rojack tries to fill the void in some unhealthy ways, drowning himself in booze or "making love to some woman who was not attractive to [him]" (3.46). In both instances, though, any relief he feels is short-lived. Rojack tries to definitively solve this problem by murdering Deborah, but though he feels revitalized, he still can't shake his feelings of dissatisfaction. With this in mind, it's clear that there's something deeper going on here.
Essentially, Rojack's problems can be traced back to that fateful night in World War II when he killed several enemy soldiers. The image of these "four men, four very separate Germans, dead under a full moon" (1.3) never leaves his mind. More than anything, this experience shows Rojack the true horror of death—but what's more, it shows him the relationship between death and the moon.
In fact, this experience sparks Rojack's absolute obsession with the moon. This affects his life in some serious ways—as a congressman, he would often "decide not to make a speech because it is the week of the full lunar face" (1.10) (yes, week). That's really just the start of it, though. At the beginning of the novel, the moon tells Rojack to commit suicide. This is a reference to various mythological tales about the moon controlling our actions, but it's also a little shout-out to werewolves, revealing just how irrational and governed by the past Rojack is.
With time, Rojack's obsession with death becomes linked to his overwhelming lust. For instance, he freely admits that he "rarely felt as if [he] were making life, but rather as if [he] were a pirate sharpening up for a raid" (4.280) when making love. In other words, he's trying to take something from these women rather than sharing something with them. So romantic.
Even the murder of Deborah is rooted in this twisted relationship between sexuality and death—after all, "murder offers the promise of vast relief" and "is never unsexual" (1.12). Although sex—and murder, for that matter—might make Rojack feel better in the short-term, it's nowhere near enough to fill up the void in his life. Taking from other people isn't the same as actually giving to himself.
Along these lines, Rojack's obsession with sex is tied to his desire to have children—little people who are of him, but not part of him. Again, then, we see Rojack's internal emptiness thriving despite his efforts to make it disappear. Yes, people often get a whole lot of personal satisfaction out of parenting… but it's hard to picture Rojack giving up his terrible ways in favor of, say, family dinners.
In Rojack's mind, though, creating new life will help him beat death. It's about his own continuity more than anything else. But that's only scratching the surface. Remember: Earlier in their relationship, Deborah got pregnant but miscarried after "a black night of drink and quarrel beyond dimension" (1.105). Rojack knows that his obsession with death—and all of the unhealthy habits that come along with it—contributed to this loss.
Although the miscarriage and its circumstances are rarely mentioned explicitly, it can be seen as one of Rojack's primary motivations. This is a guy who readily lashes out violently in response to being bested—imagine how he feels that death infiltrated his life-making efforts.
When all is said and done, however, Rojack can't change the past, no matter how much he regrets his actions. Although he does the right thing by refusing to "bury the ghost of Deborah by gorging on her corpse" (8.438) (metaphorically speaking) when confronted by Kelly, he doesn't actually become a good guy or anything like that. He's still killed Deborah. He's still manipulated Cherry and Ruta. He's still lied to the police. Yet, in the end, Rojack walks away a free man—and a rich one, at that.
This is, in many ways, the same thing that happens to Kelly. Kelly has done his fair share of messed-up stuff and still ends up a massive success—in fact, his terrible actions probably help him along in the world. The same goes for Rojack. Ultimately, then, this ending emphasizes the novel's view of the world as fundamentally absurd and irrational: In an irrational world, irrational people always end up on top.