The fledgling watchdog agency charged with ensuring U.S. counterterrorism programs do not infringe on civil liberties is moving forward with plans to probe activities conducted under a mysterious and expansive executive order.

U.S. spy agencies use Executive Order 12333, issued in 1981, to collect vast amounts of information overseas, including through the direct interception of Internet traffic from cables.

In a brisk 30-minute meeting on Wednesday in Washington, members of the Privacy and Civil Liberties Oversight Board read prepared statements about a “work plan” to perform two “deep dives” on agency practices that lean on the order.

One of the deep dives will look at a CIA program or type of collection activity, and the other will look at a National Security Agency program or collection activity.

The five-member board will draft reports on the programs but won’t necessarily release them to the public, members said, due to classification restrictions. At a minimum, the reviews will go to Congress and the White House. The board does plan to release an overview of the order to the public.

It’s unclear if the board has already decided which programs it will investigate.

“We do have some leads,” board Chairman David Medine told U.S. News with a smile. “They’re classified.”

The board already has received briefings from the CIA, NSA, FBI and Defense Intelligence Agency on how they use the order, and members expect to be briefed by remaining intelligence agencies in the near future.

Board member Rachel Brand, who cast the lone vote against the plan Wednesday, said she opposed the proposed public report because it “might attempt to make judgments” that would “risk being incomplete or simply wrong,” thus undermining the board’s credibility and institutional heft.

“We should not be in a rush to bite it off all at once,” said Brand, an assistant attorney general in the administration of President George W. Bush. “It would be impossible for the board to review everything done under Executive Order 12333, because it concerns everything done” by intelligence agencies.

“Intelligence agencies will only share information,” she warned, “if we’re credible.”

Another board member, Elisebeth Collins, said there would be value for the public in demystifying the order.

“This is not a fishing expedition,” Collins said. She said the order does include some safeguards, making the U.S. “unique in the world in having a framework that recognizes and protects [Americans’] privacy.”

The executive order made headlines in July when whistleblower John Napier Tye, formerly a section chief for Internet freedom at the State Department, warned the public it allows for the collection and indefinite retention of large amounts of U.S. Internet communications copied to servers outside the country.

The collection, Tye warned, can be done without congressional or court oversight. Future restraints on spy programs, he said, could be evaded using the order.

Some of the best-known programs exposed in 2013 by Edward Snowden – such as the NSA’s dragnet phone record and PRISM Internet surveillance programs – arguably are authorized by congressional legislation and were described to and approved by some members of the judicial and legislative branches.

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Other spy programs appear to lean on the executive order, such as the NSA's interception of communications sent between Yahoo and Google data centers and its interception of contact lists from email and instant messenger accounts.

In December, Congress voted to establish a general five-year retention limit for “nonpublic telephone or electronic communication[s]” sent by or among Americans. Critics of the provision, such as Rep. Justin Amash, R-Mich., said it for the first time stamped Congress’ approval on surveillance performed under the executive order.

Board member James Dempsey, echoing his colleagues, said “essentially everything intelligence agencies do fits within” the order. Dempsey noted the board has previously made little progress pressing for updates to attorney general guidelines governing agency-specific use of the order.

Dempsey also complained the board’s work has been hobbled by security clearance issues that have made it difficult to hire a general counsel and congressional liaison.

The privacy board was established in 2007 but remained dormant until after Snowden’s revelations. Since then, it has evaluated the NSA’s bulk phone record program, finding it unsupported by Section 215 of the Patriot Act and unnecessary for stopping terror attacks. NSA Internet surveillance activities under Section 702 of the Foreign Intelligence Surveillance Act, the board separately found, are largely appropriate and legal.