It isn’t the first time that the federal government has been caught spying on Americans or that classified government information has been leaked to the news media or otherwise widely distributed. The Vietnam War and civil-rights protest movements of the 1960s and 1970s generated plenty of surveillance and secrecy. And leaks.

But with the rise in Internet usage, there’s a far bigger audience now.

And some recent polls suggest that Americans may be more forgiving or accepting of government intrusion these days.

That may partly reflect increasing acceptance and use of online social networking sites, which create an electronic trail frequently used to target shoppers or voters.

But it also may be partly because Washington justifies its electronic snooping as an effort to prevent another 9/11-style terror attack. Many Americans may worry more today about being safe from terrorism than about government intrusions into their privacy.

U.S. authorities are weighing potential criminal charges against Edward Snowden, the 29-year-old former National Security Agency contractor and self-identified source of recent disclosures about secret government programs that collect huge amounts of phone and Internet data from law-abiding Americans.

Snowden, holed up in Hong Kong, has been both praised and vilified for his actions.

The case recalls other instances of government secrecy and ensuing leaks — from the Pentagon Papers in the early 1970s to recent wholesale dumps of classified material on the anti-secrecy website WikiLeaks.

Former Pentagon analyst Daniel Ellsberg was indicted for leaking classified government information about the Vietnam War in 1971 to The New York Times and other newspapers. A federal judge threw out the charges in 1974 because of government misconduct, including the burglary of Ellsberg’s psychiatrist’s office by the Nixon White House “plumbers” unit.

The Pentagon Papers shined a bright light on multiple governmental intentions to mislead the American public on the extent of U.S. involvement in Southeast Asia.

Ellsberg, 82, praised Snowden’s leaks to The Washington Post and The Guardian newspapers, telling The Associated Press, “There has been no more significant disclosure in the history of our country. And I’ll include the Pentagon Papers in that.”

The unpopularity of the Vietnam War and the unfolding Watergate scandal increased congressional and news scrutiny of President Richard Nixon’s efforts to involve the nation’s intelligence agencies in questionable or illegal activities.

A lengthy Dec. 22, 1974, article in the Times by Seymour Hersh detailed covert CIA programs including assassination attempts against foreign leaders and covert attempts to subvert foreign governments.

A special Senate panel headed by Sen. Frank Church, D-Idaho, investigated government intelligence gathering, digging deeply into the domestic spying activities of the Johnson and Nixon administrations. It cited numerous alleged abuses of law and of power. Some of its many recommendations — including a ban on government-sanctioned assassinations — were adopted.

Paul C. Light, professor of public service at New York University, said the Church Committee documented how “these two presidents and the FBI director manipulated intelligence and turned the system toward domestic spying, disrupting the civil rights movement and undermining the Vietnam War protests.”

They included longtime FBI Director J. Edgar Hoover’s preoccupation with civil rights leader Martin Luther King Jr. in the 1960s and early 1970s, including surveillance, wiretapping and a campaign of character assassination.

But surveillance conducted under Presidents George W. Bush and Barack Obama “is different,” Light said. “Nixon and Johnson used the intelligence apparatus to root out domestic protests, legitimate domestic protests. The more recent surveillance has been rationalized as rooting out terrorism. And Americans are much more comfortable with domestic spying designed to prevent terrorism than domestic spying designed to arrest individual citizens engaged in legitimate protests.”

The 9/11 terror attacks began changing public attitudes on surveillance, Light and other academics suggest.

In 1985, Samuel Loring Morison, a civilian Navy analyst and grandson of a famous American historian, was convicted of leaking classified satellite photographs to a British military magazine, sentenced to two years in prison and pardoned by President Bill Clinton. In 2006, Lawrence Franklin, a State Department analyst, received a 12-year sentence — later reduced — after pleading guilty to leaking classified information about Iran to lobbyists for a pro-Israel lobbying group.

In June 2010, Army Pfc. Bradley Manning was arrested for giving WikiLeaks more than 700,000 classified battlefield reports, diplomatic cables and video clips while working as an intelligence analyst in Baghdad. At his court-martial — still underway at Fort Meade, Md. — prosecutors said some information Manning divulged found its way to Osama bin Laden.

WikiLeaks founder Julian Assange remains in the Ecuadorean Embassy in London under diplomatic asylum. The British government intends to extradite him to Sweden, where the Australian activist faces questioning in a sexual assault investigation. Assange says he fears Sweden would in turn extradite him to the U.S. to face charges in the Manning leaked-documents matter and other cases.

The controversy surrounding Snowden also followed recent disclosures that the government had secretly obtained logs of some Associated Press phone calls and gathered emails of Fox News journalist James Rosen.

(AP)