It&#x27;s partially &quot;group identity&quot; and partially that they didn&#x27;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 <i>really</i> care about, like Global Warming or Abortion, and just go along with them on the other issues that they don&#x27;t care that much about.