A federal appeals court ruled Tuesday that Wikimedia has standing to challenge a National Security Agency online surveillance program, throwing out a lower court decision and sending it back to that court for further review.

Wikimedia Foundation, a nonprofit that owns Wikipedia and other "collaboratively edited reference projects," challenged the NSA's "Upstream" program, saying the government is violating its First and Fourth Amendment rights.

Wikimedia said that under Upstream surveillance "the NSA is "intercepting, copying and reviewing substantially all" text-based communications entering and leaving the United States, including their own." Wikimedia also said that "the sheer volume of [its] communications makes it virtually certain that the NSA has intercepted, copied and reviewed at least some of [its] communications."

The government has acknowledged the existence of Upstream and "disclosed some information" about the program, according to the 4th Circuit Court of Appeals decision, but "most technical details of the surveillance process remain classified."

The plaintiffs in Wikimedia v. NSA say that "Upstream surveillance involves the NSA's seizing and searching the Internet communications of U.S. citizens and residents en masse as those communications travel across the Internet backbone in the United States." The " Internet backbone" includes all the cables, switches and routers needed to send information around the world.

"The NSA performs Upstream surveillance by first identifying a target and then identifying "selectors" for that target," wrote Judge Albert Diaz in the 4th Circuit's opinion. "Selectors are the specific means by which the target communicates, such as e-mail addresses or telephone numbers. Selectors cannot be keywords (e.g., "bomb") or names of targeted individuals (e.g., "Bin Laden")."

He continued: "The NSA then "tasks" selectors for collection and sends them to telecommunications-service providers. Those providers must assist the government in intercepting communications to, from or "about" the selectors. "About" communications are those that contain a tasked selector in their content, but are not to or from the target. "For instance, a communication between two third parties might be acquired because it contains a targeted email address in the body of the communication.""

As a result of the court's analysis of Wikimedia's allegations, Diaz wrote that, "Wikimedia has plausibly alleged that its communications travel all of the roads that a communication can take, and that the NSA seizes all of the communications along at least one of those roads."

"At least at this stage of the litigation, Wikimedia has standing to sue for a violation of the Fourth Amendment," Diaz wrote in the court's opinion. "And, because Wikimedia has self-censored its speech and sometimes forgone electronic communications in response to Upstream surveillance, it also has standing to sue for a violation of the First Amendment."

The federal appeals court dismissed characterizations of Wikimedia's allegations as "speculative."

Senior Judge Andre Davis wrote an opinion concurring that Wikimedia had standing to challenge, but dissenting in part because he thought the other plaintiffs included in the suit also had standing to pursue a legal challenge against the NSA. Named plaintiffs in the case besides Wikimedia included the National Association of Criminal Defense Attorneys, Human Rights Watch, Pen American Center, Global Fund for Women, Nation Magazine, Rutherford Institute, Washington Office on Latin America and Amnesty International USA.