When hunting was the major source of food, hunters often used stalking horses as a means of sneaking up on their prey. They would synchronize their steps on the side of the horse away from their prey until they were close enough for a good shot. A stalking horse had a double benefit if the prey was an armed person. If the stalkers were discovered, it would be the horse that took the first shot.
That's what blacks are to liberals and progressives in their efforts to transform America -- stalking horses.
Let's look at it.