Widely talented individuals
The book is less a biopic about Ronald Reagan than it is a portrait of what a highly competent person's life looks like. It is a memoir in some ways, but thematically, it is clear that Reagan's story is evidence for some other argument about human nature. In this case, Reagan's early life and boundless success in a myriad of activities is like a case study on widely talented people. The memoir offers thoughtful reflections on Reagan's charisma and genius.
Humanizing public figures
Instead of showing some grandiose portrait of the subject, the memoir invites the reader into a unique point of view. We see Reagan through the hypothetical lens of childhood friendship. By inviting the reader to consider their own friends, the memoir humanizes Reagan. This has broader implications than just those pertaining directly to Reagan himself; the thematic reorientation of point-of-view invites the reader to remember that all people are just people, no matter how famous.
Competition and success
Reagan's life is defined by competition and success. The title Dutch signals this indirectly by referring to Reagan by his football nickname. That makes it clear that his competitive nature is part of what the author finds so compelling about this president. His success in politics was not something that he focused on specifically for his whole life. Instead, we see that he applies himself to whatever arena he finds most interesting, and then he wins. He wins again and again.