Idaho and Montana have both changed but not completely. Fifty years ago, even the Democrats (in the majority in the North) were conservatives. They may have voted Democrat but they supported the 2nd A and individual freedom. I don't know when the real change in demographic started but I think in the early-sixties was when the first real influx of Californians began to be noticed but there were other changes in the air. Technological change was coming to the woods and the loss of a lot of the jobs was on the horizon.
The thing to keep in mind is, the population of the entire country has doubled since then and a lot of displacement and relocation has occurred. So it is that north Idaho has filled up with people from California, New Jersey, Minnesota and elsewhere. Still, the depth of Idaho conservatism converted a large percentage of these interlopers to Idaho values rather than the other way around.
Idaho, like her neighbors, is really a little more multi-faceted than many are aware and is constantly changing. One man I knew referred to the Naples- Bonners Ferry area as "Little Appalachia" and he might not have been far off. For sure, my grandparents and great grandparents, from the Virginia and Kentucky hill country, may have brought a little of that with them. On the other hand, the other side of the family, in Boise, came from Colorado ranch stock. Thing is, they were all Idaho and I can't help but be a little proud of them. I'm sure these north Idaho citizens, wherever they come from, will do what must be done. GD