The Mexican War took place between 1846 to 1848 in the wake of the 1845 U.S. annexation of Texas.
President James K. Polk, a Tennessee Democrat and expansionist, made the declaration after a military incident in which 16 American soldiers were killed by Mexicans. The location of the incident, which was used as the justification for the war, was highly controversial: although Polk claimed that it took place on American soil, this was famously challenged by a newly elected senator from Illinois, Abraham Lincoln. The skeptical future president demanded that Polk specify, “the exact spot where American blood was shed on the American soil.” Despite this initial opposition, both the Congress and Senate would vote overwhelmingly to support of the war, after almost no debate.
The extent of popular support for the war remains unclear. While many major newspapers endorsed the war, there were many dissenting voices. A handful of anti-slavery Congressmen, including John Quincy Adams, condemned it as a way to extend the slavery system throughout Mexico (the American Anti-Slavery Society was opposed the same grounds). Henry David Thoreau and Ralph Waldo Emerson were also outspoken critics. (Thoreau was briefly jailed for refusing to pay his poll tax in protest).
There was also strong opposition from many groups of organized workers, especially in Massachusetts (which saw demonstrations against the war in Boston and Lowell). In 1846 a convention of the New England Workingmen’s Association vigorously condemned the conflict, casting it as an “unhallowed war now being waged with such inhuman results."
Articles published in the Voice echoed this sentiment. Writers were critical of the motivations for the war, of the role played by fear and patriotism in rallying the public, the disproportionate burdens of war on the working classes, and the massive amount of money spent on the war, which might have been used to help the poor. “Give me the money that has been spent in the war,” wrote one worker, “and I will clothe every man, woman and child in an attire that Kings and Queens might be proud of...I will supply that school- house with a competent teacher,” continuing, “I will crown every hill with a church, consecrated with the promulgation of the gospel of peace.”