The imprisonment as a symbol
The authors of this book allege that perhaps Thoreau's imprisonment became a kind of symbol for his point of view, because he is failing to pay his taxes as a way of rebuking the government's decision to go to war with Mexico. The imprisonment is a symbol for resistance, and it is a literal martyrdom of the government's intense reign. He suffers in the national eye, which makes the symbol's effect even more potent.
The family as metaphor
During his imprisonment, Thoreau has episodic flashbacks to memories from his life. The family in his longing desires his loneliness, because he is far from them. He is also bearing witness to great injustice without the proper avenues to confide the difficult knowledge with anyone. He sees that family is the punishment of the state—it will separate a person from their family for a long time. The symbol is a dark one.
The failure for trial
When Thoreau sees the way that racism effects the trials of those around him, he is alarmed, but no one else is. He tries to get a fair trial for a black man accused of arson, which is a poignant metaphor for racism, because the man gets sub-par treatment as if it is assumed that he will be found guilty, so why rush? The accusation is assumed to be true.
The outrage against Lydian
The second act begins with a symbolic betrayal, the same betrayal from the book of Job. His own family and confidante, Lydian, tells him that he should just concede to pay his taxes, disrespecting his stance in his opinion and outraging him. The outrage is an outward symbol for his zeal against the president, and also against those who defend imperialism.
The war in Mexico
The war in Mexico is a symbol for Thoreau, because it points to the government's willingness to let harm befall innocent people for economic and political agendas. Thoreau sees the war as an absolute evil, because the president has chosen to disrupt a balance, invading with imperial force. The war famously leads to the seizure of the Southwestern states from Mexican control.
