Final answer:
The 'clear and present danger' principle allows for the limitation of First Amendment rights when such speech poses an imminent threat to public order or national security, established by Schenck v. United States. This has evolved to consider the balance between individual freedoms and national safety, especially during times of war or emergency. Contemporary debates, such as those concerning the USA PATRIOT Act, highlight the ongoing challenge in maintaining this balance.
Step-by-step explanation:
The principle of clear and present danger was established as a standard by which the United States Supreme Court could determine when limitations on First Amendment rights were permissible. Under this principle, speech that poses a clear and present danger to public order or national security may not be protected under the First Amendment. This test was articulated in the case of Schenck v. United States (1919) by Supreme Court Justice Oliver Wendell Holmes, who compared such speech to shouting "fire!" in a crowded theater when there is no fire, hence presenting an imminent danger.
Over the years, the Court has applied this principle in different ways. While the Court no longer relies strictly on the "clear and present danger" test, it supports the notion that during times of war or emergency, speech that can harm the nation or its military forces can be restricted. For instance, speech that incites violence against the government or obstructs military recruitment could be subject to limitations. Modern-day examples of when this principle might be invoked include situations where speech may lead to terrorism or riots that threaten public safety.
However, with the introduction of legislation such as the USA PATRIOT Act, there has been ongoing debate about the balance between individual freedoms and national security. Questions arise, such as whether the government has the right to restrict expression of unpopular views or to prosecute members of the press for reporting on government programs. This continuous tension reflects the complicated relationship between upholding the First Amendment and ensuring public order and safety.