But Rep. Silvestre Reyes, the new Democratic chairman of the House Intelligence Committee, said his panel will be the judge of that.
The military and the CIA have been using a little-known power to get the banking records of hundreds of Americans and others in the United States suspected of terrorism, the New York Times first reported on Saturday.
Citing anonymous intelligence officials, the Times said that the Pentagon and the CIA have been issuing "national security letters" to financial institutions to gain access to bank records.
National security letters permit the executive branch to seek records about people in terrorism and spy investigations without a judge's approval or grand jury subpoena.
"The Department of Defense has legitimate authority in this area. This is an authority that goes back three or four decades. It was reaffirmed in the Patriot Act," Cheney said. "It's perfectly legitimate activity. There's nothing wrong with it or illegal. It doesn't violate people's civil rights."
"The Defense Department gets involved because we've got hundreds of bases inside the United States that are potential terrorist targets," he said on Fox News Sunday.
In a statement Sunday, Reyes promised that his panel would take a careful look at those claims.
"Any expansion by the department into intelligence collection, particularly on U.S. soil, is something our committee will thorough review," Reyes said.
"We want our intelligence professionals to have strong tools that will enable them to interrupt the planning process of our enemies and to stop attacks against our country," he said. "But in doing so, we also want those tools to comply fully with the law and the Constitution."
The Federal Bureau of Investigation, which is the U.S. agency designated for domestic counterterrorism activities, has issued thousands of national security letters, or NSLs, which compel companies or individuals to turn over information. The FBI does not need a warrant to obtain information if they issue a NSL.
The letters have generated criticism and court challenges from civil liberties advocates who claim they invade the privacy of Americans' lives, even though banks and other financial institutions typically turn over the financial records voluntarily.
The Pentagon and CIA versions of the NSLs are "noncompulsory," according to the Times report, but companies receiving the letters usually turn over the requested information voluntarily.
In 2005, the FBI used NSLs to secretly seek information onfrom their banks, credit card, telephone and Internet companies without a court's approval, according to the Justice Department.
The FBI delivered a total of 9,254 NSLs relating to 3,501 people that year, according to a report submitted in April, 2006 to Democratic and Republican leaders in the House and Senate. In some cases, the bureau demanded information about one person from several companies.
The Pentagon and the CIA are forbidden from traditional law enforcement roles in the United States. The Bush administration has tried since September 11, 2001 to expand the domestic surveillance powers of both agencies.
Congressional officials told the Times that members of the House and Senate Intelligence Committees had been briefed on the expanded use of the letters.
The letters "provide tremendous leads to follow and often with which to corroborate other evidence in the context of counterespionage and counterterrorism," said Maj. Patrick Ryder, a Pentagon spokesman, told the Times.
CIA officials told the Times that the agency issues a handful of national security letters each year.