Philip Roth's The Plot Against America is an alternative history text that asks the question, "What if Charles Lindbergh had won the 1940 presidential election instead of Franklin Roosevelt?" Lindbergh, who was seen as a German sympathizer at the time, attempts to assimilate the Jewish people into the American culture, causing problems that resonate across the country.

There are various themes that one can find throughout the novel. The themes of freedom, uncertainty, power, and family are strongly supported throughout the book.

Freedom is what America was built on, and it comes into question throughout the novel. Lindbergh's new Office of American Absorption encourages relocating Jewish families so that rather than living in small communities, they live throughout the country. Lindbergh believes this will help them to be seen as a part of the culture, and hopes it will dispel the rumblings of antisemitic feelings that were widespread in the 1940's. Jewish families fought back however they could, hoping to stay in their homes and communities. Lindbergh and his supporters thought that they would gain freedom by no longer feeling that they would be safe only by living in a group. These families felt their freedom was in flux and they needed to fight for their right to stay put.

Uncertainty is in the air for all Americans at the conclusion of any presidential election. A change in leadership brings about questions and concerns about what changes may come next and how they might affect everyday life. In the wake of Lindbergh's election, Jewish-Americans were fearful that their lives might be at risk if anti-Jewish rhetoric were to dominate the atmosphere. Once the assimilation efforts begin, families don't know where they'll be sent or if the new communities will accept them. Every day is filled with chance and fear.

Power dynamics are at the core of the issues between Lindbergh's faction and the general Jewish community. Lindbergh has grand plans for how to fix the country, but he does not pause to ask those effected for their thoughts on the matter. He wields his power and creates a new reality for the Jewish families. On the ground, in communities across the country, displaced Jewish families struggle for power with local antisemitic groups. Each faction wants to maintain the status quo, and fight for power for their own needs.

Family is at the heart of the struggles in the book. Within the Roth family, each member reacts differently to assimilation efforts, and the dynamic at home is affected. The Wishnow family is torn apart when Mrs. Wishnow is killed. The Lindbergh's child is kidnapped and President Lindbergh disappears, leaving his wife to put back together the pieces of the American government. The duality of family and the struggles of religion and political life come to a head in the novel where priorities constantly change and citizens are forced to identify as a part of only one group.

As in other works of "alternative history," The Plot Against America has at its core the implicit theme that history is not an inevitable process and that there is no way of being certain that events had to have a given outcome. Philip Roth's novel is somewhat akin to Sinclair Lewis's It Can't Happen Here and (more distantly) Jack London's The Iron Heel, both of which describe fascist takeovers of the United States. While this isn't exactly what happens in The Plot Against America, the premise is similar in that Charles Lindbergh's hypothetical victory in the 1940 election puts the US government into a kind of ideological alliance with Nazi Germany. Lindbergh, though an American hero for his 1927 solo flight across the Atlantic, was in fact openly anti-Semitic and, like the rest of the so-called America Firsters of that period, thought there was a "Jewish conspiracy" to force the US to enter World War II. The plausibility given by Roth to Lindbergh's being elected expresses a secondary theme that the masses in any country can easily be swayed by propaganda and rhetoric that fingers a particular group as scapegoats. Most Americans reflexively reject the idea that the US could become a racist dictatorship, but the realism with which Roth invests his story shows there is no reason this is an impossibility. The fact that the US has both slavery and the genocide of American Indians in its history quite clearly debunks the notion that "it can't happen here."

At the same time there is the theme that individual resistance against an unjust government is still possible and can be effective. In the novel, the famous radio commentator Walter Winchell is an emblem of resistance whose radio broadcasts are a beacon to the Jewish population of the US. In spite of the negativism inherent in Roth's scenario, the fact that the novel concludes with the restoration of legitimate government shows an obvious hopefulness and puts forth the message that, although historical events are unpredictable and have a randomness about them, the ultimate trajectory can be upward, and good and decency will triumph in the end.