The Supreme Court declined Tuesday to hear a challenge to a law granting broad immunity to telecommunications companies that helped the government monitor phone calls and emails.

By deciding not to hear the case, Hepting v. AT&T, the court dealt a setback to civil liberties advocates who see a dangerous abuse of power in the government's decision to grant the telecoms retroactive immunity. The justices did not comment on their refusal to hear the case.

After the attacks of Sept. 11, 2001, President George W. Bush waived a safeguard requiring federal judges to sign off on search warrants before the government could obtain a wiretap. The New York Times exposed the warrantless wiretapping program in 2005.

Amidst questions about the legality of the wiretap program, Congress passed a 2008 measure -- supported by Sen. Barack Obama -- shielding telecoms involved in the initiative from lawsuits. Under the new law, the U.S. Justice Department could nullify such legal action by vouching for the telecoms.

Critics have warned that law unjustly inoculated both the telecommunications industry and the government against being held accountable for breaking the law. The American Civil Liberties Union and the Electronic Frontier Foundation sued, saying that Verizon Communications, Sprint Nextel, and AT&T had violated the privacy of customers.

The Supreme Court is not done weighing the scope of the government's post-Sept. 11 surveillance powers. An upcoming case on the court's docket, Clapper v. Amnesty International USA, concerns a provision in the Foreign Intelligence Surveillance Act authorizing the government to monitor communications between Americans and terror suspects living overseas.

A group of journalists, attorneys and human rights workers has sued the government over FISA, saying that because their work involves communicating with potential terror suspects, their private communications could be intercepted.