Question: is don't tread on me?
Answer: The tread in Gadsden's defiant phrase, don't tread on me, means “to step, walk, or trample so as to press, crush, or injure something.” And so, with its tongue flicked, fangs out, and body coiled in defense, the rattlesnake (and motto) warns: “If you dare put your foot down on me, I will strike.”