Nathaniel Prentice (or Prentiss) Banks (January 30, 1816 – September 1, 1894) was an American politician from Massachusetts and a Union general during the Civil War. A millworker, Banks became prominent in local debating societies and entered politics as a young adult. Initially a member of the Democratic Party, Banks's abolitionist views drew him to the nascent Republican Party, through which he won election to the United States House of Representatives and as Governor of Massachusetts in the 1850s. At the start of the 34th Congress, he was elected Speaker of the House in an election that spanned a record 133 ballots taken over the course of two months.
At the outbreak of the Civil War, Abraham Lincoln appointed Banks as one of the first political major generals, over the heads of West Point regulars, who initially resented him, but came to acknowledge his influence on the administration of the war. After suffering a series of inglorious setbacks in the Shenandoah River Valley at the hands of Stonewall Jackson, Banks replaced Benjamin Butler at New Orleans as commander of the Department of the Gulf, charged with the administration of Louisiana and gaining control of the Mississippi River. He failed to reinforce Grant at Vicksburg, and badly handled the Siege of Port Hudson, taking its surrender only after Vicksburg had fallen. He then launched the Red River Campaign, a failed attempt to occupy northern Louisiana and eastern Texas that prompted his recall. Banks was regularly criticized for the failures of his campaigns, notably in tactically important tasks, including reconnaissance. Banks was also instrumental in early reconstruction efforts in Louisiana, intended by Lincoln as a model for later such activities.