Final answer:
The case of New York Times Co. v. United States was an important step toward the idea of freedom of the press, reinforcing press freedoms against government-imposed prior restraint.
Step-by-step explanation:
An important step toward the idea of freedom of the press was established in the case of New York Times Co. v. United States. This landmark decision is famously known as the Pentagon Papers case, where the Supreme Court ruled that the government could not exercise prior restraint to stop the publication of the Pentagon Papers by the New York Times and Washington Post. This Supreme Court case reinforced the importance of press freedoms in the context of national security and the public's right to know.