MONTPELIER -- The USA Patriot Act has been misinterpreted, legal experts say, and the National Security Agency is collecting billions of data - everything from text messages to Google map pins and cellphone records - without probable cause from millions of Americans who have never committed a crime.

Sen. Bernie Sanders says the question is: "How do we protect people from a terrorist attack, but do it in a way that does not undermine our democracy and the privacy rights that make us a free country?"

Sanders brought two legal experts - David Cole, a Georgetown University Law School professor, and Heidi Boghosian, the head of the National Lawyers Guild - to a town hall meeting in Montpelier to answer that question on Saturday.

Cole and Boghosian detailed how corporations are collecting personal data, including credit card purchases, and selling that data to aggregators who in turn give the information to the government. They see broad collection of data from citizens as an invasion of personal privacy that should be protected under the Fourth Amendment.

The NSA collects 5 billion records per day on cellphone locations of private citizens; 200 million text messages a day; 180 million records from credit card companies; email chats and Internet histories, GPS data, smart phone app data such as Angry Birds, according to Sanders. Court, tax and birth records are online. Google maps can pin a person's location within a few yards.

The extent to which the NSA is snooping on private citizens was unknown until last year when Edward Snowden, an IT contractor, leaked information about the agency's activities. The NSA uses computers to filter billions of data points to determine whether Americans are involved in terrorist activities. The information is stored at hosting sites in Utah.

Sanders says the NSA's practices, which were approved by President Barack Obama, but were not vetted by Congress, put the privacy Americans expect in jeopardy. It also has the potential to harm democracy, he said.

"What does freedom mean if the U.S. government knows about every call you're making, has your banking records and knows who your friends are?" Sanders said. "Is that what a free society is about?"

Freedom, he says, is "very subtle," and it can be undermined by self-censorship when people begin to fear that the government is looking over their shoulders. If you look at an Al-Qaida website or check a book out on terrorism, Sanders says, "You'll be on a list for sure." The sense that the government is watching affects what people talk about and what they write about.

Cole says the NSA is keeping a record of just about everything. "I go pick up my daughter at school, and I text 'where are you' she sends me a text, 'I'll be right out,' and I send another text 'where are you,' and she sends me a text, 'I'll be right out,' and then I send her a text, 'where are you?' The NSA is keeping a record of every one of those communications and storing it at a data center in Utah for five years, even though my daughter and I are not planning a terrorist act."

Cole says James Clapper, the head of national intelligence, lied to Congress in March 2013 when he told lawmakers the NSA was "not wittingly" collecting data. "He lied to keep it secret from us," Cole says. Last month, members of Congress asked the Obama administration to fire Clapper; the president defended him.

We should be concerned, Cole said, when the government is adopting broad snooping programs and lying about them to keep them secret.

"Privacy matters," Cole said. "There's a reason why the Fourth Amendment protects our privacy and protects us from unreasonable searches and seizures. Privacy is essential to liberty, to political freedom, to the ability to talk and associate without having the government watch over you at every turn. I don't think privacy is dead. People still close doors to houses, doors to bedrooms and put passwords on computers.

"Who would want to live in a world without privacy?" Cole said. That is the world of George Orwell's 1984, Ray Bradbury's Fahrenheit 451, and Spielberg's Minority Report."

Much of the information the government has about Americans comes from corporations that have developed technologies that track everything we do, Cole said, and "those technology developments have radically changed the calculus with respect to privacy in the modern era."

In the old days (less than 20 years ago), if the government wanted to know where you went, what you were reading, what you were listening to and who you hung out, they could find that out, but they'd have to spend incredible resources to spy on you or get a warrant and search your home, Cole said.

Back then, the government still couldn't find out what you were hoping, desiring or thinking about, he said. Now, everything we do leaves a virtual trace. Every time you click on a link, "you are telling somebody else - an Internet provider or cellphone provider or a bank or a cred card company - what you're thinking about."

"The government now has the ability to get information on business records on everyone of us without showing that any one of us has been guilty of wrongdoing," Cole said.

The government's rationale, he said, is that all information is potentially relevant to a terrorist investigation.

"What the government used to be able to do because they had probable cause you were engaged in some wrongdoing they can do now without a warrant, without probable cause, without any idea of wrongdoing.That is a radical transformation in the relationship of we the people to the government."

Boghosian described the extent to which corporate aggregators and financial institutions work with the government. Choicepoint, Experian, Texas Instruments, local law enforcement agencies, and homeland security fusion centers all aggregate data and disseminate it to national intelligence agencies.

The largest corporate aggregators have operated in a shroud of secrecy, she said.

Choicepoint, for example, works with 35 government agencies, including the FBI, the DEA, U.S. marshalls, the IRS and the ATF.

"Each day we learn more about the close relationship between corporations and the government," Boghosian said, and the way in which institutions "operate without scrutiny and violate the law with impunity."

The only way the snooping will come to an end, is if Americans insist that "we want to use the Internet and use a cellphone to call a child or use our credit card to make a purchase, but we don't want to give that information to government just because we live in the modern world," Cole said.

The good news, Cole says, is that there is bipartisan support for reform of the NSA that would end "dragnet" collection of data and instead would only allow intelligence agencies to access information when they can show there is a reason to believe the records pertain to someone they suspect is engaged in terrorist activity. There are 30 bills in Congress that would clamp down on the NSA's surveillance activities, including the USA Freedom Act, co-sponsored by Sen. Patrick Leahy, D-Vt.

The issue, Sanders says, is non-partisan. Members of Congress on the right and the left are alarmed by the extent to which the government has become Big Brother. "If you believe in limited government, how can you not be in opposition to what the NSA is doing?" Sanders said. "The conservatives are coming out and saying the right things. It's bringing together strange bedfellows, but it's also bringing together strange bedfellows in support of what the government is doing."

Rep. Peter Welch, D-Vt., who was also at the town hall, says Congress doesn't know how much the government spends on intelligence activities because that information is currently classified. Welch has introduced a bill that would require the president to include the total dollar amount requested for each intelligence agency in his annual budget.