How did Carter lose OK?

[DS0816]

Jimmy Carter, the Democratic pickup winner elected the 39th president of the United States in Election 1976, narrowly missed a host of states. He was dealing with making up a loss of 23.15 percentage points by the 1972 nominee of his party, South Dakota U.S. Sen. George McGovern. McGovern carried only one state, Massachusetts, and District of Columbia. Carter shifted every state in the nation (no exceptions) in his direction. It was a national shift of 25.21 percent to win over the U.S. Popular Vote, in a Democratic pickup, by 2.06 percentage points. Had Carter won by an additional three percentage points, that theoretically (I'm not assuming uniformity of shift) would have take him from 23 states to at least five more. That also would have sent his prevailing 297 electoral votes to much closer to 397 electoral votes as he would have also won pickups in the likes of California, Illinois, New Jersey, Oregon, Virginia, and maybe even Oklahoma (carried by Gerald Ford with a margin of 1.21 percentage points). Part of why Carter didn't win even bigger was the alignment of the map (base states for a then-Democratic Party being in the "south" and a then-Republican Party being in the "north").