(Ivan Sekretarev/AFP/Getty Images)

Three former National Security Agency employees who exposed secret government programs defended Edward Snowden during a Thursday event at the National Press Club.

"Manning, Snowden – I stand with them without equivocation," former NSA senior executive Thomas Drake said. Like Pfc. Bradley Manning and Snowden, Drake was charged with violating the Espionage Act. Drake contacted a Baltimore Sun reporter in 2005 about wasteful NSA programs, including the Trailblazer Project, which aspired to snag vast quantities of Internet data, but instead reportedly cost taxpayers $1.2 billion before being cancelled.

The charges against Drake were later dropped.

Certain parts of the government "have become a criminal enterprise," Drake said, and Snowden's only option "was to escape the United States of America."

After Snowden revealed the massive NSA phone and Internet surveillance programs in June, President Barack Obama and other senior government officials defended the programs as essential for national security. Administration officials claim the programs prevented dozens of terror attacks, but all publicly disclosed examples have been contested.

Sens. Ron Wyden, D-Ore., and Mark Udall, D-Colo., members of the Senate Select Committee on Intelligence, said they were presented with no evidence that the collection of phone records prevented even one attack.

Drake said Snowden almost certainly would have been detained if he did not flee to Hong Kong before releasing top secret documents on the surveillance programs conducted by the NSA. He cited a provision first included in the 2012 National Defense Authorization Act allowing the government to detain Americans citizens "engaged in hostilities against the United States" without trial.

Former NSA Technical Director William Binney and former NSA senior analyst J. Kirk Wiebe offered similarly supportive comments.

Binney and Wiebe worked with Drake – whose involvement was not initially disclosed – and two other NSA employees to expose to government oversight officials in 2002 the Trailblazer Project, which was allegedly selected over a less-intrusive, less-expensive alternative. They argued the program violated the Fourth Amendment, squandered taxpayer money and made intelligence-collecting overbroad and therefore less effective.

"I don't know what other choice he had," Binney said of Snowden's decision to become a fugitive. "He felt his only option was to leave the country and I don't blame him."

"They made it impossible for us to work [and] they threatened us with prosecution for years," recalled Binney, who said the FBI raided his home, and the homes of his colleagues, in 2007 after they complained about the Trailblazer Project.

Binney, sitting in a wheelchair for the discussion, tore into the NSA program Stellar Wind, which he said allowed NSA analysts to construct a social network of any American citizen's personal and professional relationships. Bulk collection of email and other Internet data through that program began in late 2001 and continued two years under President Barack Obama, the Guardian reported in June.

"If all of this was legal, why did [telecom companies] need retroactive immunity?" Binney asked. He said 85 percent of NSA employees are "really introverted people working on code and ciphers. ... They aren't really the kind who would expose a lot of things." But even introverted NSA workers were concerned about far-reaching NSA programs, he claimed.

"You have no freedom of association without the NSA knowing about it," Binney said. "It's a matter of software." He said the recent Boston Marathon bombing and the 2009 Ft. Hood massacre might have been prevented if intelligence-collecting was more focused.

Wiebe recalled leaving his NSA job in disgust on Oct. 31, 2001. He accused former NSA Director Michael Hayden of unilaterally revoking the Fourth Amendment, which guards citizens against unwarranted searches, and said the NSA's "self interest, ego and arrogance led to 9/11."

Complaining of programs through officially authorized channels, as some critics suggested Snowden should have done, "resulted in nothing good for anyone" in his case, Wiebe said.

"We've become the enemy we're trying to thwart," he charged.