When Sergeant McShane comes to the Nolan house, it is the first time that Francie has seen him without his uniform. After playing with Laurie for a bit, Sergeant McShane states his wish to marry Katie. Katie worries, briefly, about the possibility of a public man like McShane having a scrubwoman for a wife. However, he insists that she’s a good woman and a better man would be lucky to marry her. Katie agrees to marry McShane because he is a good man and she would like to have him for a husband.
Katie’s decision to marry McShane has none of the romance of her marriage to Johnny. It is, instead, a practical decision made by two people who admire each other and desire companionship. Though there’s some attraction between them, this seems to matter less than what they can offer each other: Katie offers McShane a healthy child and he offers financial stability.
Sergeant McShane makes it clear to Francie and Neeley that he doesn’t wish to replace their father, but he would like to adopt Laurie, since she has never had a father. Francie and Neeley think of what an easy life Laurie will have, given McShane’s financial security. On the other hand, she also won’t have all of the fun they did during their hard times.
Now that they have put their impoverished pasts behind them, Francie and Neeley can see how their poverty made them creative and gave them a greater appreciation for the small things they could afford. Laurie will have a better life, but she won’t develop those skills.