My land. We're here, and we're gonna stay here. Give me ten years and I'll have that brand on the gates of the greatest ranch in Texas. The big house will be down by the river, and the corrals and the barns behind it. It'll be a good place to live in. Ten years and I'll have the Red River D on more cattle than you've looked at anywhere. I'll have that brand on enough beef to feed the whole country. Good beef for hungry people. Beef to make them strong, make 'em grow. It takes work, and it takes sweat, and it takes time. Lots of time. It takes years.*
That scene, and the one immediately following, which jumps 15 years into the future to show that Dunson does indeed succeed in raising that many cattle, establishes Dunson as a driven man who has a plan and the will to see it through, regardless of — in fact, aided by — legal and moral uncertainties. He is a man with the requisite ego to act on Manifest Destiny.
The opening scenes of There Will Be Blood (2007) show Daniel Plainview to be equally driven. We see him working a claim on a silver mine, alone, enduring an accident which leaves him with an apparently broken leg and possible internal injuries, before he arrives in the nearest town (presumably after crawling through the dessert to get there) to cash in. While Dunson associates (genuinely or not) his claim with the future success of the country, Plainview's goals appear to be more solitary. The work of both men, however, advances the infrastructure and, mostly, the economy of the developing nation.
Both of these films are Westerns — Red River more obviously so, set amid the trappings of traditional Westerns like cattle drives, American Indians, and quick-draw shoot-outs, but There Will Be Blood also, for much of it is set in the last period of the Old West amid not the territorial but the economic expansion of the country. Both lead characters are bold, brave, determined to stake a claim on the frontier and defend it above all else, bullying, not always likable, at times detestable, at times amoral, at times immoral. In short, most likely the kind of people who really did settle the American West. Both films show these men attempting to realize a difficult plan in pursuit of wealth, and becoming increasingly isolated as their bludgeoning personalities make it increasingly difficult for them to work with others.
The two men also have a conflicted relationship with religion. Tom appears to be a Christian, with "I'll read over him" (in reference to reading scripture at a funeral service) becoming his refrain. His devoutness is called into question, however, by the fact that some of the men he reads over are men he has himself killed. Daniel is more obviously at odds with religion. After paying lip service to landowners concerned about his religious beliefs, and after being humiliated by Eli, an ambitious preacher on whose father's land Plainview builds his fortune-making rig, Daniel's "victory" over Eli (and, symbolically, the Church) at film's end seems to cap not only his freedom and career, but his unspoken life's ambition.
* Though I am not suggesting 2001: A Space Odyssey as part of a potential triple feature, this speech of Dunson's nonetheless reminds me of the prehistoric segment of that film. After being visited by the monolith, the primates discover that bones can be used as weapons. There is dramatic emphasis on how one group uses bones to kill members of another group, allowing the former to expand and dominate. Prior to this, however, emphasis is placed on the killing of an animal for food; shortly after the kill the group is shown eating meat, presumably for the first time, and eating lots of meat — a piece of raw flesh dangling from practically every primate hand. The infusion of that much protein into their diet — and this is something I picked up elsewhere, not directly from 2001 — allowed carnivorous primate brains to grow larger, giving them an evolutionary advantage and allowing them to expand and eventually evolve into the dominant species. Dunson's mention of beef, hungry people (by which he doubtless means White settlers), and time — "lots of time" — brings to mind this evolutionary process. While it doesn't qualify as an evolutionary advantage, certainly their great numbers, and not their weapons alone, enabled White settlers to overwhelm the native civilization (at least according to "Hollywood history" — see mentions of the relentlessness of the white onslaught in Dances With Wolves and Little Big Man, e.g.). Such numbers needed infrastructural support, and the raising of cattle contributed not only to that infrastructure, but to the need to annex more and more land on which to raise more and more cattle.