Missouri, the state created under a compromise in 1820, became the bellwether state in Presidential elections from 1904 to 2004.
Missouri, always considered a Midwestern state, was one of the border states that did NOT join the Confederate States of America during the Civil War, despite having slavery.
Missouri, with the cities of St. Louis, Kansas City, and Springfield, trending Democratic as most cities did, however saw the rural parts of the state trending Republican as the years went by, and those three cities now represent less percentage of the population than they did in 1990.
So the evangelical Christian Right has become much more of the dominant influence in the rural areas, and Barack Obama could not win Missouri either in 2008 or 2012, and lost by a substantial margin in 2012.
It is now clear that Missouri is trending Republican more and more, and is much more like Arkansas, Louisiana and Mississippi, than it is like its neighbors of Iowa, Wisconsin and Minnesota!
Therefore, it is clear that Missouri is now a Southern, rather than Midwestern, state, and that the lack of population growth in St. Louis, Kansas City, and Springfield, together less than 20 percent of the state population, will make it difficult for any Democrat to win the state in a Presidential election.
The only reason for Claire McCaskill holding her Senate seat and Jay Nixon being Governor is their ability to come across as a conservative Democrat, and to have GOP opponents who are not well liked by the Missouri population.
So the bellwether state of Missouri is no more!