THE PRIVACY and Civil Liberties Oversight Board, established on the recommendation of the 9/11 Commission, is meant to provide independent oversight to ensure that national security and counterterrorism programs are conducted with appropriate protections for civil liberties. But the board has been unable to perform its oversight role since January, when two members stepped down — months after the board's chairman resigned. So it comes as welcome news that President Trump has named the well-qualified Adam Klein to chair the commission.

In the wake of Edward Snowden's revelations of large-scale warrantless surveillance, the board's reports on the National Security Agency's authorities provided transparency and accountability and helped shape legislation restraining one of the NSA's more controversial programs. Its bipartisan composition — of five members, a maximum of three may belong to the same political party — bolsters its independence and evenhandedness.

But by the board's rules, three members must be present to conduct business. And the second-to-last member, Rachel Brand, left the board in February to become associate attorney general. This leaves the only remaining member, Elisebeth Collins, able to continue ongoing investigations but without the power to begin probes or issue recommendations — key components of the board's mission.

A functioning board is particularly important in the current moment, as both the House and Senate intelligence committees struggle to balance their usual oversight of the intelligence agencies with their investigations into Russian election interference. And with the looming expiration in December of Section 702 of the Foreign Intelligence Surveillance Act — which authorizes widespread NSA collection of the content of foreign communications for intelligence purposes — the board has an important role to play. Whatever one's opinion of Section 702, the presence of a functioning and evenhanded supervisory body would be a reassuring sign of the government's intention to take privacy and civil liberties seriously as Congress considers how best to reform or reauthorize the statute.

This reassurance is international as well. The board's presence contributed to a European Commission finding that the United States provided adequate privacy protections for E.U. citizens' data — a decision crucial to the ability of American companies such as Google and Microsoft to do business in the European Union. For the board to remain dormant would likely damage the United States' standing on privacy matters in the E.U.

The Senate should confirm Mr. Klein, a former clerk for Justice Antonin Scalia. Mr. Klein has thought deeply and carefully about the board's responsibilities and has been a longtime advocate for its rejuvenation. Then the administration should continue working to get the board to a quorum and fully staff it, consulting with Democratic leaders in Congress to settle on nominees for the board's two minority positions. Mr. Klein's nomination is a good step — but a first step only.