All you have to know to understand the odd point of view of this book, and its significant omissions, is that the writer has turned out to be an admirer and de facto defender of Jerry Falwell and a lot of his Republican exploits. This hardly seems to be based in any kind of analysis of day-to-day normality of everyday Catholics actually being more liberal than people understand.
Winters is a good writer, and this is a thoughtful and engaging book, although it does slant left. Essentially, the bulk of the book is a history of Catholics and the Democratic party.
This book is really smart. It goes all the way back to FDR and the New Deal to discuss how Catholics have been involved politically with the Democrats.