In Pollock's play, Walsh, the letters included take place between James Walsh and his wife Mary, as he is stationed in the Northwest Territory of Canada (at Fort Walsh) and Ottawa, where Walsh's family lives.
The content of this correspondence serves several functions. First, it is through these letters that the audience learns that Walsh's job has isolated him from the world at large—and even from his family.
You'll think I've got a touch of prairie fever, but the solitude here, the emptiness of these Great Plains, fills me with a sense of timelessness.
Second, it shows too that the world outside of the Northwest Territory is unaware of the demands, the politics and the heartbreak that a leader such as James Walsh faces. First is Mary's statement of the propaganda and/or rumors reaching Ottawa (a center of civilized life, far removed from Fort Walsh):
Here in the East, we're always hearing grand tales of Major Walsh...how he's subdued the Sioux and Sitting Bull.
This is, of course, far different from what is actually taking place: he admires Sitting Bull, but also sympathizes with the dilemma of the Sioux people...as seen in Walsh's description of the conditions Sitting Bull's tribe faces:
Sickness, plain suffering kills them like flies. Most of the ponies are dead...and their rotting carcasses are cut up for food...Yes, they're starving and destitute, yet they endure. They share what little they have...and they observe the law. Goddamnit, they'd be a credit to any community...
Third, it shows the internal struggle that Walsh faces in trying to remain ethically focused on doing what he believes to be right while also following orders at the same time. And he finds that he is disappointed by the government he has served:
One thing I know, across the line there's been gross and continual mismanagement of the Sioux. An able and brilliant people have been crushed, held down, moved from place to place, cheated and lied to...And now, they hold on here in Canada, the remnants of a proud race, and they ask for some sort of justice...which is what I thought I swore an oath to serve!
Walsh's lines to Mary about his memories of their first years of marriage, and their newborn daughter, give us the sense that besides the passing of time, Walsh is experiencing a sense of loss: he fondly remembers his wife looking eighteen even as she reports grey hairs, and that Walsh wouldn't recognize her. This might also infer that they have not only grown apart, but that Walsh is not the man he was when they first married and started a family. We might also infer that he longs for days when he found life simpler. For there is no question that he is torn between honoring the Sioux, a people he admires, with a leader that he says he understands, who also understands him. For Walsh, the answer to the Sioux problem is clear and simple: caring for them out of human decency rather than offering them up as "pawns" in a political game between the British and American governments.