On July 24 or July 25, 1846, Thoreau ran into the local tax collector , Sam Staples, who asked him to pay six years of delinquent poll taxes . Thoreau refused because of his opposition to the Mexican–American War and slavery , and he spent a night in jail because of this refusal. The next day Thoreau was freed when someone, likely to have been his aunt, paid the tax, against his wishes.  The experience had a strong impact on Thoreau. In January and February 1848, he delivered lectures on "The Rights and Duties of the Individual in relation to Government",  explaining his tax resistance at the Concord Lyceum . Bronson Alcott attended the lecture, writing in his journal on January 26:
It is in vain, sir, to extenuate the matter. Gentlemen may cry, Peace, Peace²but there is no peace. The war is actually begun! The next gale that sweeps from the north will bring to our ears the clash of resounding arms! Our brethren are already in the field! Why stand we here idle? What is it that gentlemen wish? What would they have? Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it, Almighty God! I know not what course others may take; but as for me, give me liberty or give me death!