The US should conduct a holistic reappraisal of its laws and authorizations to balance privacy, civil liberties and surveillance across the public and private sectors, former National Security Agency director Bobby Ray Inman has told the Guardian.

In an extensive interview, Inman, a legendary NSA director, strongly defended the agency's bulk surveillance of phone records and internet communications, and criticized members of Congress who want to restrict it as ignorant of the way the programs operate.

But he also warned that intelligence officials have an obligation to tell the truth about surveillance in their public statements.

The hour-long phone interview represented Inman's first public comments on the Edward Snowden controversy that has engulfed the agency he ran in the 1970s. Inman, a former deputy CIA director and retired navy admiral, was an architect of the first major surveillance reform, the Foreign Intelligence Surveillance Act of 1978.

"I'm not going to make a case to you that revisiting all the terms of the Patriot Act is justified," said Inman, 82, now a professor at the University of Texas-Austin. "I would be very comfortable with specific authorization for collection and controls on how it's done. That's how we started out originally in this process.

"Let's be realistic that this is a problem that's been generated in large measure with the explosion of communications. It's the internet, mobile phones … the quantity of communication globally is just exponentially higher than I had to deal with in 1977-81. That's why I'm a little reluctant to sit back and second guess, not having been involved in the decision, how you went about each step in trying to deal with this reality.

"It is a different world. And does that mean it may be worthwhile going back and looking at authorizations, process issues?" Inman continued. "I would urge that if you're going to do that, [you have to] look at privacy issues in the private sector, not just the government. I personally find it offensive that it's fine for X corporation to have everything on you but not the government to know. That's a basic don't-trust-your-government argument, which I think erodes democracy."

Bobby Ray Inman in 1983. Photograph: Wikimedia Commons

Asked if that meant he advocated a re-evaluation of US rules on surveillance in the government and private sector, Inman, pictured left in 1983, replied: "Yes, because you go back to update the authorizations, the procedures, based on how has the nature of communications changed."

Inman argued strenuously that the bulk collection of Americans' phone records is appropriate in light of a terrorist threat he considers to be mutating, and characterized critics of the surveillance as isolationists, grandstanders and hypocrites.

"I don't have a problem with the bulk collection, as long as there are rigid controls on how you can actually access what was said," Inman said.

Documents leaked by Snowden and published in the Guardian suggest that the NSA's controls are less than rigid. Among them are indications that the NSA possesses the authority to search through databases of foreign emails, phone calls and associated data for Americans' names and identifying information, something Ron Wyden, an Oregon Democrat on the Senate intelligence committee, calls a "backdoor search" capability.

The Wall Street Journal reported last week that the NSA has the capacity to access 75% of traffic across the US internet and can "retain the written content of emails sent between citizens within the US and also filters domestic phone calls made with internet technology."

Inman is no fan of the bulk surveillance's critics in Congress – particularly Wyden, whose criticism he called a "disservice to this nation" – and framed the growing discomfort with the surveillance programs within a broader debate about America's international role.

"If your view is that the US should not play a significant role in the world, and we should simply pull back to Fortress America, get rid of all the economic agreements and go back to the happy 1930s [and the] early days after world war two, when less than 3% of our GDP came from international trade," Inman said, "… if you want to go back to that world and a lower standard of living, then you can stop much of this intelligence collection activity. But I suspect you won't have ended the terrorist threat to this country."

Inman criticized legislative skeptics of the bulk surveillance – who came close in the House of Representatives in July to ending NSA's bulk collection of American phone records – as intentionally and self-servingly ignorant.

"The current process would allow the doubters within the government, those who are members of Congress, to know what's what. They don't want to spend the time," Inman said.

While Inman said he had "enormous admiration for Dianne Feinstein and Mike Rogers," the intelligence committee leaders in the Senate and House, both of whom strongly support the bulk surveillance, he said he had "no sympathy for any member of Congress who says they're uninformed or didn't understand.

"Any member of Congress can go to the spaces of the select committee files, but they have to be restrained and abide by security constraints attached to the information. That will inhibit going on their favorite talk show to enhance their re-election opportunities."

Inman declined to criticize James Clapper, the embattled director of national intelligence who recently apologized for untruthfully telling Wyden that bulk collection of Americans' data was "not wittingly" occurring. But Inman said it was "a problem" that intelligence officials had at times mischaracterized the extent of their surveillance activities.

"That does erode confidence, certainly in the Congress," Inman said.

Speaking generically, Inman said: "I had an absolute flat rule: you will not lie to the Congress. You don't have to go volunteer everything you know if you're trying to protect sources and methods, but if they ask you for it, you tell them, or say I cannot discuss in open session."

Inman last made headlines in 2006, when he told a New York audience that the NSA's warrantless surveillance activities were "not authorized" and the Bush administration needed to "get away from the idea that they can continue doing it," as reported by Wired's Noah Shachtman. He was the rare ex-NSA senior official to criticize the effort.

Inman clarified that his problem was not with the activities themselves, but with its status outside the approval of the Fisa court he helped create and the surveillance law he helped shape. The passage of the 2008 Fisa Amendments Act laid his concern to rest, he said.

Longtime observers of Inman's career see statements like those as consistent with his contrarian streak.

"Bobby Ray is probably one of the brightest people I've ever talked to on the subject of intelligence," said historian Matthew Aid. "There's plenty of room to disagree with him on things, but he has a better perspective – a 1970s, 1980s perspective – on civil liberties and the role of the intelligence community in doing its job than current intelligence practitioners do."

Aid said he ranked Inman "at the top of all the NSA directors I have looked at."

Former NSA mathematician turned whistleblower and bulk-surveillance critic William Binney worked at the NSA under Inman.

"I did not know him personally; but, I never had questions about his management of directives," Binney emailed. "I think he and General [William] Odom were two of the best directors the NSA has had."

As NSA director, Inman –who was later nominated by Bill Clinton to run the Pentagon, only to abruptly withdraw – could be a "not quite predictable" figure, said Steven Aftergood of the Federation of American Scientists.

"He was a vigorous leader and defender of the NSA," Aftergood said. "In fact, he was so vigorous that he clashed with scientists and cryptographers over public access to cryptography and freedom to publish in areas of national security science."

Inman questioned the willingness of Americans to give large quantities of data to telecoms firms, internet companies and other corporations, but not to the government.

"I asked my students: if you don't worry about [your data] being held in commercial databases, why do you worry about the government having it?

"It touched off a very heated debate among them, and they finally came back to me and said: well, if there's a valid need, they don't mind if the government has it; they just don't want their parents to know what they accessed, and where they went on the internet."

Aid noted that many civil libertarians find corporate data troves to be similarly problematic.

"Before Edward Snowden reared his ugly head, it was and remains an issue about how much information companies like Google, Microsoft and Yahoo and every other corporation in America retains about us: our credit card numbers, our URLs," he said.

"It is scary how much data is available in the hands of corporations.I t's not a new debate but it's an issue I think we should as a nation should consider as part of this overall debate about NSA surveillance powers over all."