The National Security Agency remains adamant about the necessity of its vast surveillance of Americans, despite revelations about the widening scope of those intrusive operations. It will be up to Congress to put needed restraints on the NSA's massive collection of personal phone and computer records, including emails.

Gen. Keith Alexander, head of the NSA, told the Senate Judiciary Committee on Wednesday that the agency "can't go back to a pre-9/11 moment." He maintained that the NSA's extended reach is an indispensable weapon in the ongoing battle against terrorism.

But no reasonable critic expects the NSA to go back to a pre-9/11 position. The 2001 radical Islamist terror attack on America was a flash point in history requiring a broad response known as the War on Terror.

Because of it, the U.S. launched lengthy, costly military missions in Afghanistan and Iraq, and created the Transportation Security Administration, which has subjected airline passengers to unprecedented scrutiny, once including intrusive full body scans at commercial airports.

The reaction to 9/11 also initiated a growing NSA program of spying on Americans - the "metadata" scope of which was not imagined until renegade NSA contractor Edward Snowden started making it public earlier this year.

Mr. Snowden's continuing stream of information - it could hardly be described as a leak at this point - indicate that the NSA has relentlessly stretched its sweep for data, gathering private phone and computer records by a variety of methods. The agency has even hacked major Internet servers, according to documents made public by Mr. Snowden.

During Wednesday's hearing, Judiciary Committee Chairman Patrick Leahy, D-Vt., pointed out that NSA officials have acknowledged the phone surveillance program has proven particularly valuable in only one instance involving terrorism.

"Just simply because you can do something, does it make sense to do it?" Sen. Leahy asked.

Apparently, the NSA's answer is yes, privacy be damned.

There have been repeated assurances from NSA officials - and President Barack Obama - that the personal data is merely being collected, not listened to or read.

Is that really supposed to ease Americans' justified concerns about the government's growing and ready access to their personal records?

Existing safeguards against violations of privacy rights obviously aren't doing the job. For instance, the Foreign Intelligence Surveillance Court has served as a virtual rubber stamp for the NSA's expanding - and often excessive - surveillance requests.

Sen. Charles Grassley, R-Iowa, aptly observed that the NSA's activities "call into serious question whether the law and other safeguards currently in place strike the right balance between protecting our civil liberties and our national security."

That's why Congress must intervene with necessary oversight to curb the NSA's vast and unwarranted seizures of Americans' personal data.

As Sen. Leahy said Wednesday: "We give up a lot of our privacy in this country, and frankly I worry about giving up too much."

In this case, we already have.