Polk was an early pioneer of the [[Bush Doctrine]] of [[preventive war]], launching an invasion of [[Mexico]] to prevent an imminent Mexican attack on [[Texas]]. Unfortunately, Polk was unable to prevent several thousand Mexicans from entering the country and gaining citizenship when the United States annexed [[California]] and [[New Mexico]]. Polk has also been criticized for accepting a compromise settlement with [[England]] over the [[Oregon]] Country instead of pursuing a preventive war with [[Canada]] in order to gain all of it. | Polk was an early pioneer of the [[Bush Doctrine]] of [[preventive war]], launching an invasion of [[Mexico]] to prevent an imminent Mexican attack on [[Texas]]. Unfortunately, Polk was unable to prevent several thousand Mexicans from entering the country and gaining citizenship when the United States annexed [[California]] and [[New Mexico]]. Polk has also been criticized for accepting a compromise settlement with [[England]] over the [[Oregon]] Country instead of pursuing a preventive war with [[Canada]] in order to gain all of it. |