Washington is ablaze with war fever. President James K. Polk has sent Congress a sweeping message documenting nearly two decades of Mexican offenses—unpaid indemnities, attacks on American citizens and ships, broken treaties—culminating in the declaration that Mexico's recent provocations "would justify, in the eyes of all nations, immediate war." The Daily Union's editorial, "The Call of the Crisis," captures the moment's electricity: Mexican forces have allegedly invaded Texas territory and shed American blood on the battlefield. The paper reports that Louisiana's legislature has already passed emergency resolutions unanimously—without even calling for a roll-call vote, as one legislator feared recording a dissenting voice would imply the possibility of doubt. Southern states are mobilizing with "spontaneous energy" and "elemental popular momentum." The Executive awaits Congress's sanction to unleash "the fires of our army." Party divisions have evaporated; Americans North and South now speak only as patriots defending American soil.

This May 1846 edition captures America at the precipice of the Mexican-American War, a conflict that would fundamentally reshape the nation's borders and deepen the slavery question that would splinter it seventeen years later. The tensions detailed here—over Texas annexation, unpaid claims dating to the 1820s, and competing visions of hemispheric power—had been simmering since Texas won independence in 1836. What's striking is the *unanimity* the Union celebrates. The war would have broad support initially, but it would also become deeply controversial among Northern Whigs and abolitionists who saw it as a land grab to extend slavery westward. The Southwest's fervent mobilization visible in this paper contrasts sharply with the opposition building in Boston and New York. This moment of apparent national consensus masks the sectional fracture about to explode.

• The paper casually mentions Mexico agreed to recognize Texan independence in summer 1845 'on condition that she would not annex herself to any other power'—yet Texas annexation happened anyway. This technical violation of Mexico's conditional recognition is presented as legally irrelevant because 'Mexico had no right to prescribe restrictions,' a breathtaking assertion of American sovereignty that would have infuriated Mexico City.
• A joint claims commission awarded American citizens $2,026,139.68 in damages against Mexico by 1840—but Mexico paid nothing on time. Of the remainder, $928,627.88 in claims was approved by American commissioners but left undecided by the umpire. By 1843, Mexico had paid only the interest due, leaving seventeen unpaid installments 'now due.' The war, in part, is being fought over accounting.
• The paper reveals President Polk took unilateral action in September 1845—he 'deemed it important' to position armies on the frontier 'without previous authority of Congress'—then sought clarification from Mexico about whether they intended war. Mexico's November response: they'd renew diplomatic relations. This measured reply contradicts the 'invasion and blood' narrative dominating the front page.
• The Union's editorial demands action with biblical urgency: 'every principle of civilization and every attribute of Divine Power fights on our side.' The framing of this territorial dispute as a moral crusade sanctified by God reveals how Americans of the era cloaked imperial ambitions in righteousness.
• The paper advertises subscription rates and notes 'subscribers will be notified days in advance when their subscriptions will expire'—suggesting reader churn was significant enough to warrant explicit notice policies. The mechanical precision of newspaper business contrasts sharply with the revolutionary fervor on the front page.

• This edition explicitly credits Texas leaders' request for federal protection as justification for stationing troops on the Rio Grande—but the Texan invitation was politically convenient. By war's end, the U.S. would acquire 525,000 square miles of Mexican territory (modern California, Nevada, Utah, most of Arizona and New Mexico, and parts of Colorado and Wyoming), making this the largest territorial expansion since the Louisiana Purchase.
• President Polk's December 1845 message, reprinted here, mentions a treaty of April 11, 1839, and another of January 30, 1843—evidence the U.S. had *already* pursued legal remedies and negotiation for years before war became inevitable. Yet the editorial dismisses discussion itself: 'Now is not the hour for discussion.' War was preferred to further treaties.
• The Southern unity celebrated here—Louisiana passing war resolutions by acclamation—would shatter within a decade. The Mexican-American War's territorial gains would spark the Compromise of 1850, the Kansas-Nebraska Act, and ultimately the Civil War. The 'patriotic unanimity' of May 1846 was the last moment before slavery's question consumed American politics entirely.
• Polk positioned troops 'between the Nueces and the Del Norte' (Rio Grande) in territory Mexico considered its own, then claimed defensive posture. The Nueces River was Texas's traditional southern boundary; the Rio Grande lay 150 miles further south. This wasn't defense—it was occupation of disputed land, the match that lit the powder keg.
• The Union's editors invoke Mexico as a 'neighboring sister republic, which, following our example, had achieved her independence'—yet the paper justifies treating her with contempt unavailable for European powers. The paternalism is stunning: Mexico is scolded like a wayward sibling who needs discipline, not a sovereign nation.