Censorship during the Mexican War
Censorship during the Mexican War (1846-1848) marked a significant departure from previous conflicts in the United States, as it was the first war extensively reported on by newspapers without government or military censorship. Daily newspaper coverage, driven by war correspondents who provided firsthand accounts from the front lines, greatly influenced public perceptions of the war and its implications. This journalistic freedom allowed for a more accurate and detailed portrayal of events compared to official military dispatches. Interestingly, the lack of censorship also extended to dissenting voices; opposition to the war, particularly from radical Whigs, was largely unrestrained, allowing for a robust public discourse.
Despite some military concerns about potential leaks or negative coverage, the Polk administration did not resort to silencing dissent, reflecting a significant commitment to civil liberties during this period. The absence of substantial censorship enabled the American public to form more informed opinions regarding the war. This environment of free expression and reporting was not typical of later conflicts, highlighting how the Mexican War set precedents for war reporting and public engagement. Overall, the Mexican War illustrated the complexities of wartime communication and the balance between military secrecy and the public's right to know.
Censorship During the Mexican War
Issues arising from the lack of censorship during the Mexican War influenced later U.S. government wartime censorship.

The Mexican War was the first American war reported daily in newspapers across the country. The American public followed the conflict with great interest and anticipation. Newspaper reports did more to influence American attitudes toward the war than any other medium. They also molded American perceptions of the war, its causes, and its effects on the United States. Remarkably, government and military censorship of newspaper reports did not exist.
Newspapers used war correspondents for the first time to report from the front lines in Mexico and the Southwest. These reporters followed the campaigning American armies and occasionally participated in the fighting. Instead of rehashing often late and nondescript military dispatches, reporters wrote firsthand accounts that fed the American public’s desire to know more about the war. War correspondents rapidly and efficiently wrote their stories and sent them off to press. Their stories proved not only more plentiful but also more accurate than their military counterparts. No military or government authority censored their stories. Although some in military and government circles complained about the lack of censorship, the large audience reached by the newspapers had a positive effect. The journalistic freedom exercised by newspapers provided Americans more information about this war than previous ones. Thus, the American people may have been better able to form informed, intelligent opinions about the conflict.

Dissident opinion against the war also enjoyed widespread freedom. The government did not attempt to silence those who spoke out against “Mr. Polk’s war”—namely, radical Whigs. President James K. Polk publicly complained about opposition to the war, but charges of treason for opposing the war rarely occurred. Authorities did not constrain civil liberties. The Polk administration worried that dissident opinion might affect the prosecution of the war, but not to the point of taking drastic measures to curb opposition. While the war was not without controversy over which side started the conflict and what motivated the United States in the war, censorship had yet to become standard practice. War correspondents informed the American public. Sketch artists, so prevalent in the Civil War, provided uncensored visual depictions of battles to American readers. This freedom caused concern, notably among the military, who worried that reporters might unintentionally leak secret information to the enemy, and that negative reporting might turn public opinion against military action. Journalistic freedom and dissident opinion did not enjoy such freedom in later conflicts.