Constantine's Sword is not a good work of history or theology, but it does fit well into the genre of contemporary literature where authors carry their readers along on their personal journeys to greater awareness and knowledge.
If we look at Carroll's work this way, we can be grateful to it for bringing some very important questions to the attention of the general public, in a forum perhaps more effective than many others. And if we read this book as his personal "confession" (my preferred subtitle rather than his "a history"), then we also can read it with full freedom to disagree with his conclusions.
Carroll's questions I find generally correct. However, his answers are at best often ill-framed. Irritating the Church structures--true to Carroll's own roots in American counter-culture--is really not the way to accomplish even the soul-searching that needs to precede any potential changes. And Carroll's last section, his call for a 'Vatican III,' does precisely this, I'm afraid. His questions need to be couched in such a way that they can be first heard, listened to, and then dialogued with.
Dr. Langer's review of "Constantine's Sword" is available on the website of the Center for Christian-Jewish Learning at Boston College.