A powerful US surveillance law is set to expire – what happens now?

Donald Trump’s bid to install a controversial ally as the country’s leading intelligence official has shone a light on the wide reach of a powerful surveillance law, and raised questions over its future.

Privacy advocates say it deserves scrutiny, and reform, regardless of who the US president appoints as director of national intelligence (DNI).

A key provision of the Foreign Intelligence Surveillance Act (Fisa) is due to expire on Friday night amid a backlash to Trump’s announcement that Bill Pulte, head of the Federal Housing Finance Agency and a major Republican donor, would be acting DNI.

While Trump has moved to contain the furor – announcing his nomination of another top official, Jay Carney, to take the role on a permanent basis – US Congress has so far failed to extend section 702 of Fisa in time for Friday’s deadline.

While the Pulte row brought Fisa back in the spotlight, the program’s balance of civil liberties and national security has been the subject of fraught debate in recent months, and years.

“If Bill Pulte had never become part of the conversation, many of the underlying concerns about section 702 – if not all of them – would still exist,” said Jason Pye, vice-president of the Due Process Institute, a bipartisan nonprofit focused largely on criminal justice. “These debates didn’t start in this Congress, and they didn’t start with this administration.”

Section 702, first enacted in 2008, allows national security agencies to collect and review texts and emails sent to and from foreigners living outside the US, without a warrant. If an American is talking to a non-American target living abroad, their communications can get swept up too.

Privacy advocates say that while the law is intended to surveil foreigners outside the US, the federal government uses this loophole to spy without warrants on Americans, an unconstitutional practice. Intelligence agencies say they need these surveillance powers to prevent terror attacks.

This year, Congress has only been able to pass short-term reauthorizations of the section 702 program. Trump and Republican leaders in the House of Representatives have tried, unsuccessfully, to push through longer extensions that do not include key reforms demanded by a broad coalition including progressive Democrats and far-right Republicans.

In late April, Congress punted the original section 702 expiry date to 12 June, after negotiations failed to lead to a lengthier renewal.