This is an important book at a time where the United States retreats into another phase of isolationism. The book by Charles Kupchan provided an excellent history of the motivation, discussions, and decisions on US isolationism from the founding of the country to the present day. The book shows that strategic isolationism is not necessarily a bad thing, but the motivations and the extend of the national isolation are important.
The initial isolationism following the founding of the USA seemed well founded. The USA tried to isolate itself from the turmoil in Europe, especially between the large colonial powers. The USA could afford the isolation due to the protection of two oceans, the abundance of resources, and the ongoing westward expansion on the north American continent.
The industrial revolution virtually shrank the oceans. As the westward expansion came to an end and the USA enjoyed a new economic power in the global competition, the national isolationism was soften to allow participation in the developments in central and south America. One key event was the Spanish war in 1898/99. However, isolationism had an additional, ugly side which was based in deep racists believes. Therefore new US territory was not, even upon request by the territories, formally included in the union.
While the US dappled in international collaboration during World War I, the floodgates broke open during World War II leading to the defeat of fascism in Europe and resulting in a new role as a global superpower.
Two concepts are carried through the narrative which seem problematic at least to a first generation immigrant who was not indoctrinated in US schools - "American exceptionalism" and the "redeemer nation." The author unfortunately stopped short on examining these concepts in detail and w.r.t. isolationism, pax Americana, and the USA as global police force.
This book is highly recommended and was very captivating and enjoyable as audiobook.