LitCharts assigns a color and icon to each theme in Cat’s Cradle, which you can use to track the themes throughout the work.
Science and Morality
Religion
Governance, Politics, and Nationhood
Absurdity and Meaninglessness
Summary
Analysis
John starts to open up to the idea of being president but assumes there must be a catch. Frank explains that there is a catch: John would have to marry Mona. It says in The Books of Bokonon, explains Frank, that she will marry the next president.
The “catch” is, of course, no such thing for John. He has been fixated on Mona since he first saw her picture in a magazine.