What was the dividing line between north and south

Few rights are more critical to a well-functioning democratic system then free speech. consider the difference between the supreme court's statement in schenk v u.s. (1919) the government has the power to punish speech that poses "a clear and present danger" to the functioning of the government and its statement in texas v. johnson (1989) that "government may not prohibit expression simply because it disagrees with its message." how did the court's position on speech evolve in the 70 years between these two cases?