Recently, this urgent headline from the Electronic Frontier Foundation, the leading organization defending our rights — specifically in the digital world — caught my attention: “In Response to the NSA, We Need a New Church Committee and We Need it Now” (Cindy Cohn and Trevor Timm, June 7).

During the 1970s, like many Americans, I was shocked and alarmed to learn that the National Security Agency even existed. Exposing it and the FBI’s shredding of our Bill of Rights was Democratic Sen. Frank Church of Idaho, chairman of the Senate Select Committee to Study Governmental Operations With Respect to Intelligence Activities, known as the Church Committee. The committee released reports on its investigations of American intelligence in 1975 and 1976.

A courageous constitutionalist, Church probed the FBI and the CIA for secretly digging into our lives; he especially focused on the NSA. The Cato Institute’s Vice President Gene Healy reports on one example of the Church Committee’s findings:

“Under ‘Project Minaret,’ from the early 1960s until 1973, the NSA compiled watch lists of potentially subversive Americans, monitored their overseas calls and telegrams, sharing the results with other federal agencies” (“’It can’t happen here’ just did,” Healy, Washington Examiner, June 10).

Citing the Church Committee’s findings, Healy writes that “ordinary citizens involved in protests” were among those being monitored.

And in a direct warning to We The People, Healy quotes Church, who in 1976 told us “such is the (NSA’s) capability to monitor everything — telephone conversations, telegrams, it doesn’t matter. There would be no place to hide.”

And, as I wrote in my book, “The War on the Bill of Rights and the Gathering Resistance” (Seven Stories Press, 2003), Church pledged: “The American people need to be assured that never again will an agency of the government be permitted to conduct a secret war against those citizens it considers threats to the established order.”

Church, among other civil libertarians at the time, worked hard to ensure that pledge. So what happened?

To begin, few Americans — including school kids — probably know Frank Church’s name today. And though the senator was the first to expose the NSA in its bastion of Orwellian secrecy, we know his dire warnings of its continually expansive scope were ignored.

As Glenn Greenwald reported a few weeks ago in the U.K.’s Guardian: “The National Security Agency is currently collecting the telephone records of millions of U.S. customers of Verizon … under a top secret court order” (“NSA collecting phone records of millions of Verizon customers daily,” Greenwald, The Guardian, June 5).

Even if the valiant Church couldn’t safeguard our Constitution from the NSA, current members of Congress have promised to investigate its formerly secret collusion with the Obama administration. There is also much concern among Americans of diverse political allegiances.

But for how long will this last?

For example, any vision I had of Barack Obama testifying at his eventual impeachment trial was suddenly dimmed by the results of a poll conducted by the usually credible Pew Research Center (done with The Washington Post): “A majority of Americans — 56 percent — say the National Security Agency’s (NSA) tracking the telephone records of millions of Americans is an acceptable way for the government to investigate terrorism” (“Majority Views NSA Phone Tracking as Acceptable Anti-terror Tactic,” people-press.org, June 10).

Furthermore, Pew found that Americans have supported government efforts to investigate terrorist threats, “even at the expense of personal privacy,” since Sept. 11.

But this “new normal” of the president trading the Constitution in for the government’s collection of our thoughts and actions is older than that day.

In the early 1950s, when I was a reporter on a Boston radio station, I went to a lecture at Harvard University given by a high-level official in J. Edgar Hoover’s FBI. A member of the audience asked him heatedly about the FBI’s wide-ranging secret spying on Americans suspected of communist ties.

He looked at this woman in the audience complaining of Hoover taking away our privacy, and, with a sort of half-smile, he told her: “There is no privacy anymore.”

The audience was stunned silent. (Meanwhile, I’ve never forgotten J. Edgar Hoover once telling us to “imagine an FBI agent standing behind every mailbox.”)

Yet the Pew poll doesn’t convince me that public passivity will continue.

We are, without exaggeration, in one of the most crucial periods of American history. We can prevent terrorists around the world from eventually having their way with us if we stop our unconstitutional government from denuding us of who we are as Americans. Otherwise, what are we defending?

(Nat Hentoff is a nationally renowned authority on the First Amendment and the Bill of Rights. He is a member of the Reporters Committee for Freedom of the Press, and the Cato Institute, where he is a senior fellow.)