Until 1964, Oklahoma was considered a "swing state" in American politics, shifting back and forth in its support for the two major parties. This was in part due to Oklahoma's situation both as a part of the Great Plains states, which tended to be reliably Republican, and the South, which was heavily Democratic at that time.
Prior to 1964, Oklahoma was a politically unpredictable state, shifting back and forth between supporting the two major political parties. This was due to its position in the Great Plains region, which leaned Republican, and the South, which was predominantly Democratic.