The US Supreme Court on Tuesday blocked a lawsuit brought by human rights groups and others challenging a US government electronic surveillance program set up after the September 11, 2001 attacks.
In a 5-4 ruling the justices said the plaintiffs -- which include Amnesty International USA and the American Civil Liberties Union (ACLU) -- had no legal standing to bring the case because they could not prove that they personally suffered from the government program.
The program at issue is the Foreign Intelligence Surveillance Act (FISA), which was expanded in 2008 to let US intelligence agencies monitor international phone calls and emails in hopes of thwarting potential terrorist plots.
The justices did not address whether the program is constitutional, but rather whether the plaintiffs could present their constitutional challenge.
The decision was split along ideological lines, with the conservative majority ruling in favor and the four moderate judges voting against.
In the case, Clapper vs. Amnesty International, the administration of President Barack Obama asked the top US court to throw out the suit.
Government lawyers argued on behalf of James Clapper, director of national intelligence, and maintained that because the surveillance targets foreigners, the plaintiffs had no standing to sue.
The plaintiffs, which also included attorneys representing prisoners in Guantanamo and media organizations, maintained they could sue because their own private communications could also be intercepted in the electronic monitoring.
"We hold that respondents lack ... standing because they cannot demonstrate that the future injury they purportedly fear is certainly impending," read the majority ruling, written by Judge Samuel Alito.
"It is highly speculative whether the government will imminently target communications to which respondents are parties," Alito wrote.
An appeals court had earlier ruled in favor of the plaintiffs, stating that their fear of being monitored was not "paranoid or unreasonable."
Justice Stephen Breyer, writing the dissenting opinion, said there is "a very high likelihood" that the government will intercept "at least some of the communications," which include discussions with family members of those detained at Guantanamo, friends and acquaintances of those persons, and investigators, experts and others."