Reichsminister Doktor Goebbels wrote:

In 2004 there were only 2 issues bush voters ever mentioned. The ONLY issues, not taxes, not the war, not anything of substance, were these 2: Abortion and Fags. If abortion and fags weren't their issues, and for the professed majority they weren't, they were voting republican because they had always voted republican. Brand loyalty. My Grandpappy voted republican, my Daddy voted republican, and I'm voting republican by gum!

I've heard this, and maybe agreed with it at times. But it might be a misunderestimation of the people to whom you spoke. Calling it mere "brand loyalty" overlooks that the brand is identified with a philosophical position. When somebody says "I voted that way because I'm Republican," they might be guilty of mindless sports fan behavior, or they might consider the party's philosophical platform sufficiently inherent to the party name that "I'm a Republican" is just shorthand for "I believe in things X, Y, and Z, and so do the Republicans, to a greater or lesser degree, so I want them in charge."