When you use Google or Yahoo, the National Security Agency can secretly monitor and collect data on everything you view or communicate, according to leaked documents revealing the latest privacy-shredding excess of the nation’s electronic sleuths.

In a covert project called MUSCULAR, the NSA and its British counterpart broke into the main fiber-optic links that globally connect Google and Yahoo data centers, according to The Washington Post. Using that access, the agencies can intercept in real time the content of communications such as texts, audio and video, and funnel massive hauls of data from user accounts in the companies’ internal networks to NSA data warehouses at Fort Meade in Maryland.

Because the tapped cables are outside the United States, legal restrictions on domestic surveillance don’t apply and the Foreign Intelligence Surveillance Court has no jurisdiction. That’s apparently the point for the NSA since, under a different program known as PRISM, it can gain access to online accounts if the court approves.

With each leak from former NSA contractor Edward Snowden, the NSA looks more and more like an agency gone rogue. Officials there seem determined to duck every legal restriction on their spying, and to thwart any attempt at oversight. Congress can’t let that continue.

The advance of technology has made the distinction between domestic surveillance, with its appropriate constitutional constraints, and spying abroad, where there are few if any restrictions, increasingly meaningless. The situation demands congressional hearings to uncover what the NSA is doing, to determine whether it’s legal and acceptable, and to help lawmakers devise ways to make sure the agency stops trashing the rights of Americans.