Neither side took any further action to avoid a war. Meanwhile, Polk settled a major territorial dispute with Britain via the Oregon Treaty, which was signed on 15 June 1846. By avoiding any chance of conflict with Great Britain, the United States was given a free hand regarding Mexico. After the Thornton Affair of 25–26 April, when Mexican forces attacked an American unit in the disputed area, with the result that 11 Americans were killed, five wounded, and 49 captured, Congress passed a declaration of war, which Polk signed on 13 May 1846. The Mexican Congress responded with its own war declaration on 23 April 1846.
Neither side took any further action to avoid a war. Meanwhile Polk settled a major territorial dispute with Britain via the Oregon Treaty, which was signed on 15 June 1846. By avoiding any chance of conflict with Great Britain, the United States was given a free hand regarding Mexico. After the Thornton Affair of 25–26 April, when Mexican forces attacked an American unit in the disputed area, with the result that 11 Americans were killed, five wounded, and 49 captured, Congress passed a declaration of war, which Polk signed on 13 May 1846. The Mexican Congress responded with its own war declaration, on 23 April 1846.