The "crazy Western states"- Utah, Idaho, Wyoming- will probably never vote Democratic again. The GOP is entrenched there to an insane degree, partly by tradition but mostly because of the states' far-right orientation. I would be stunned if any Democrat could poll 45 percent in the next half-century.
Some huge swings:
Kansas 1928 GOP wins 58.2-40.8
Kansas 1932 Dem wins 53.5-44.1
Georgia 1972 GOP wins 75.0-24.6
Georgia 1976 Dem wins 66.7-33.0
New Hampshire 1984 GOP wins 68.7-31.0
New Hampshire 1988 GOP wins 62.5-36.3
New Hampshire 1992 Dem wins 38.9-37.7-22.6
New Hampshire 1996 Dem wins 49.3-39.3
Kansas 1928 was actually 72-27 Republican. But anyways- it was the Depression that caused the shift.
Georgia was Jimmy Carter.
New Hampshire was Perot and the white collar recession.
These kind of swings are not likely to happen in the Mountain West. It could actually be argued that Utah is trending Republican further- Carbon County used to be reliably liberal, but it's been increasingly Republicanized.