The dominant purpose of the First Amendment was to prohibit the widespread practice of government suppression of embarrassing information.
— Justice William O. Douglas

Landmark Free Speech Cases

Outside the National Archive Building which houses our country's most precious documents including the Constitution and the Bill of Rights is a statue proclaiming, “Eternal vigilance is the price of liberty.” It reminds Americans that in a democracy freedom isn't free, that we must be ever watchful to protect our hard-won freedoms from those who would take them from us.

If, as judges ruled in Mayer v. Monroe County Community School Corporation case, teachers had no right of free speech in class, many landmark free speech cases could not have been heard in court. Cases are listed in chronological order. As you study the decisions pronounced over time, it is likely you will notice that in recent years, the courts have continued to narrow free speech rights for both teachers and students. Why? It's time to ask that question. Why must the rights of American citizens be more and more restricted by the courts as our country matures as a democracy? It doesn't make sense. If the price of liberty is eternal vigilance, it's time we pay attention.

Pickering v. Board of Education , 391 U.S. 563 (1968)
http://caselaw.lp.findlaw.com/scripts/getcase.pl?navby=case&court=US&vol=391&page=563

The problem in any case is to arrive at a balance between the interests of the teacher, as a citizen, in commenting upon matters of public concern and the interests of the State, as an employer, in promoting the efficiency of the public services it performs through its employees." By a 8-1 vote, the Court held that school officials do violate the First Amendment when they terminate a public school teacher for speaking out as a citizen on matters of public concern.

Tinker v. Des Moines School District, 393 U.S. 503 (1969)
http://caselaw.lp.findlaw.com/scripts/getcase.pl?court=us&vol=393&invol=503

First Amendment rights, applied in light of the special characteristics of the school environment, are available to teachers and students. It can hardly be argued that either students or teachers shed their constitutional rights to freedom of speech or expression at the schoolhouse gate. This has been the unmistakable holding of this Court for almost 50 years.