Recent leaks about surveillance programs at the U.S. National Security Agency show an agency with little regard for the U.S. Constitution and laws on the books, two past NSA leakers said Wednesday.Leaks by former NSA contractor Edward Snowden published early this month give more evidence of widespread privacy violations at the NSA, said former NSA employee Thomas Drake. "We need to confront the reality that we have a secret government that's not operating in our best interests," Drake said at the Computers, Freedom and Privacy Conference in Washington, D.C. "What's at stake is the very essence of what it not only means to be an American, but also what it means to be a citizen."Drake and former NSA employee William Binney said Snowden's leaks confirmed many of their past warnings about the NSA's growing surveillance efforts in recent decades. Following the 9\/11 terrorist attacks on the U.S., officials at the agency and President George Bush's administration chose to disregard the U.S. Constitution and laws against surveillance of U.S. residents and allow the agency to sweep in their communications, said Drake, who was indicted on 10 felony counts that were later dropped.After 9\/11, Drake said he witnessed the "United States government, in the deepest of secrecy, unchaining itself from the Constitution."The NSA and Bush administration "revoked" the Constitution's Fourth Amendment, giving U.S. residents freedom from unreasonable searches, and "violated the legal regime" against domestic spying that the NSA had operated under since the late 1970s, he added.An NSA spokeswoman disputed assertions that the agency is violating civil liberties."Without a doubt, one of the biggest misconceptions about NSA is that we are unlawfully listening in on, or reading e-mails of, U.S. citizens," spokeswoman Vanee' Vines said in an email. "This is simply not the case. NSA is unwavering in its respect for U.S. laws and Americans' civil liberties. What's more, our compliance processes are a part of a broader oversight structure in which all three branches of government play a key role."Binney said he believes that the NSA is not recording most phone calls because it would be too cumbersome, with 10 billion to 12 billion phone calls made each day worldwide. But the former technical leader for intelligence at the NSA estimated that the agency actively wiretaps 500,000 to 1 million people worldwide.There are no strong checks on the NSA's collection power, Binney said. "There's no privacy at all," he said.The NSA's collection of phone records and metadata is still a privacy violation, even though the agency says it's not connecting names to the data, said James Bamford, an author of five books on the NSA. "The [phone] number is the name," he said.The danger of the mass collection of data by the NSA is that it "buries" analysts in data, said Binney, who developed a surveillance program called ThinThread intended to allow the NSA to look at data but not collect it. The NSA dumped that program in favor of more extensive data collection."The biggest problem was getting data to a manageable level," he said. "We didn't have enough people, we couldn't hire enough people east of the Mississippi to manage all the data we were getting. The idea of collecting too much data is as bad as not being able to collect enough."Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is email@example.com.