Five years ago this month, news organizations broke stories about federal government surveillance of phone calls and electronic communications of U.S. and foreign citizens, based on classified documents leaked by then-National Security Agency contractor Edward Snowden. The initial stories and subsequent coverage sparked a global debate about surveillance practices, data privacy and leaks.

Here are some key findings about Americans’ views of government information-gathering and surveillance, drawn from Pew Research Center surveys since the NSA revelations:

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Privacy today faces growing threats from a growing surveillance apparatus that is often justified in the name of national security. Numerous government agencies—including the National Security Agency, the Federal Bureau of Investigation, the Department of Homeland Security, and state and local law enforcement agencies—intrude upon the private communications of innocent citizens, amass vast databases of who we call and when, and catalog “suspicious activities” based on the vaguest standards.

The government’s collection of this sensitive information is itself an invasion of privacy. But its use of this data is also rife with abuse. Innocuous data is fed into bloated watchlists, with severe consequences—innocent individuals have found themselves unable to board planes, barred from certain types of jobs, shut out of their bank accounts, and repeatedly questioned by authorities. Once information is in the government’s hands, it can be shared widely and retained for years, and the rules about access and use can be changed entirely in secret without the public ever knowing.

Our Constitution and democratic system demand that the government be transparent and accountable to the people, not the other way around. History...

The cellphone is rapidly becoming the most universal accessory among human beings anywhere in the world. The expansion of its use and capability has made the cellphone not just a communications device but the planner, personal computer, mapping mechanism and record storage device for most people.

It has another function that most people do not fully appreciate: tracking device. The use of the cellphone as a surveillance tool is at the heart of a major privacy case heard by the Supreme Court this week in Carpenter v. United States. At issue may be the very future of privacy in America. This argument is occurring almost 50 years to the day that the court issued its historic decision in ...