On this day in history: U.S. Congress declares war on Mexico

On May 13, 1846, the U.S. Congress overwhelmingly votes in favor of President James K. Polk’s request to declare war on Mexico in a dispute over Texas. Under the threat of war, the United States had refrained from annexing Texas after the latter won independence from Mexico in 1836. But in 1844, President John Tyler restarted negotiations with the Republic of Texas, culminating with a Treaty of…