There are other American Federal Laws that are referred to as "Espionage Acts" besides just this one. As a practical matter, most felons are conviced and tried under these Acts of Congress, rather than going about the very difficult process of trying and convicting someone for Treason. In many cases, the maximum penalty for espionage is the same as that for treason - including imprisonment for life or possibly execution.
Publications which the Wilson Administration determined were guilty of violating the Act "were subject to being deprived of mailing privilege, a blow to most periodicals," according to Sidney Kobre's book Development of American Journalism. A section of the Act allowed the Postmaster General to declare all letters, circulars, newspapers, pamphlets, packages and other materials that violated the Act to be unmailable. As a result, about 75 newspapers either lost their mailing privileges or were pressured to print nothing more about World War I between June 1916 and May 1918. Among the publications which were censored as a result of the Act were two Socialist Party daily newspapers, the New York Call and the Milwaukee Leader. The editor of the Leader, Victor Berger, was sentenced to 20 years imprisonment after being convicted on a charge of conspiracy to violate the Act; this was later reversed on a technicality. Other publications banned from the mails were the Industrial Workers of the World (IWW) journal Solidarity, American Socialist, bohemian radical magazine The Masses, German-American or German-language newspapers, pacifist publications, and Irish nationalist publications (such as Jeremiah O'Leary's Bull).
Later court decisions have cast serious doubt upon the constitutionality of the Espionage Act, including Brandenburg v. Ohio (which changed the "clear and present danger" test derived from Schenck to the "imminent lawless action" test), New York Times Co. v. United States, and United States v. The Progressive, Inc., although none of these decisions directly overruled it.
During and after World War I, the Espionage Act and the Sedition Act were used in some prosecutions that would be considered constitutionally unacceptable in today's United States, even in the political climate after the September 11, 2001 attacks on New York's World Trade Center. While many of the laws were repealed in 1921, major portions of the Espionage Act remain part of United States law (18 USC 793, 794). The libel decision of New York Times Company v. Sullivan (1964), by granting enhanced protection to criticism of public figures, including government officials, largely eliminated what remained of the crime of sedition in the United States.
The United States Congress has enacted other laws to protect specific types of privately held information including:
Note that some of the aforementioned acts either are related to very personal and private data of individuals and companies, such as health records, the contents of personal computer hard drives, or secrets used by manufacturers to gain a competitive advantage, or, when related to records of government activities, they prohibit unlawful disclosure of a secret by someone lawfully privy to the secret in question. Unlike the Espionage Act, they do not prohibit disclosure by someone who merely obtained the secret (i.e. whom the secret was leaked to) from someone lawfully privy to it.
As a general rule, even if the Espionage Act were construed to be Constitutional, the publication of alleged state secrets obtained by non-governmental personnel may not be interfered with by the government; only the act of publishing may be punished, after the fact; see prior restraint.
The important exception to this doctrine is the so-called "troop-ship exception", which relates to the dissemination of information that is likely to result in extraordinary endangerment of national security, and to loss of life, such as the disclosure of the position of a flotilla of troop-ships in a time of war, or the actual schematics and specifications (as opposed to the theory of operations) of a nuclear weapon.