New disclosures about the National Security Agency continue to raise more questions about its ominous capacity to collect a vast amount of American citizens’ electronic communications.

Last Wednesday, The Wall Street Journal reported that the NSA routinely collects about 75 percent of all email communications in the United States.

For three years the agency collected millions of personal communications of Americans without a court order, in violation of the Fourth Amendment and criminal law. Those violations reportedly ended last year.

But more troubling news came Friday as the NSA acknowledged that analysts deliberately violated privacy rights on multiple occasions over the past few years.

The wide-ranging scope of the NSA’s effort, and the fact that a secret federal court has accused it of repeatedly making misleading statements about its illegal activities, both underscore the fact that the agency lacks adequate oversight to protect Americans’ privacy.

Supporters of the NSA’s programs to collect communications from virtually anywhere on the globe insist that they are critical to the nation’s ability to identify threats from terrorists and others before they materialize. They contend that American civil rights are protected.

For example, they note that the NSA is only authorized to intercept telephone calls and Internet communications when they do not involve “U.S. persons,” broadly meaning anyone in the United States.

To intercept the communications of those individuals the NSA needs specific permission from a secret federal court, known as the Foreign Intelligence Surveillance Court (FISC).

Following last week’s disclosures, however, the government released an edited transcript of a disturbing FISC decision issued in October 2011, in which Judge John Bates summed up a six-month investigation by his court into ongoing violations of the law and constitutional protections of privacy by the NSA.

He not only found that the agency had for three years collected perhaps millions of communications between Americans not subject to investigation, but that it had not informed the court of the practice.

Furthermore, said Judge Bates, “The court is troubled that the government’s revelations regarding NSA’s acquisition of the Internet transactions mark the third instance in less than three years in which the government has disclosed a substantial misrepresentation regarding the scope of a major collection program.”

The top lawyer for the intelligence community, Robert Litt, said the illegal collection was caused by a technological problem the NSA itself uncovered, and that it wasn’t an intentional effort to collect American communications.

But that doesn’t absolve the NSA of repeatedly trying to mislead the court.

President Obama has insisted that the NSA “is not spying on Americans.”

Yet with each new troubling disclosure of the agency’s long reach into Americans’ personal communications, those reassurances ring increasingly hollow.

It is clear that the layers of protection supposedly built into the NSA’s communications intercepts fail to preserve Americans’ privacy rights.