It's partially "group identity" and partially that they didn't care about issue X enough to hold onto that idea. I feel like people identify with parties in the

It's partially "group identity" and partially that they didn't care about issue X enough to hold onto that idea. I feel like people identify with parties in the U.S. based on its position on a few issues they really care about, like Global Warming or Abortion, and just go along with them on the other issues that they don't care that much about.