Allegations of potential abuse by the Bush administration involving domestic spying is a "very serious issue," said Sen. Chuck Hagel, R-Neb., Wednesday.

Hagel said he was one of four members of the Senate Intelligence Committee calling this week for a joint inquiry by the Senate judiciary and intelligence committees on alleged domestic spying abuses by the Bush administration.

"We don't have all the facts," Hagel said. "We know some things based on revelations that have come out, but we need to know more facts."

Hagel said oversight is needed any time when the government is spying on American citizens because of the potential of abuse.

"The civil rights of Americans must always be protected," he said.

While there are people plotting harm to America, the United States was founded on a set of laws rooted in the concept of civil liberties and personal rights, he said.

"The Bill of Rights are our precious rights and you cannot violate those rights under any circumstances," Hagel said.

But while Hagel recognizes that there are extraordinary circumstances where domestic spying is necessary for national security reasons, he said there are right and wrong ways to go about it.

"We must find the equilibrium and center of gravity that protects our national security as well as our civil rights," Hagel said. "We have been able to do that for more than 230 years."

He said that accountability is what's at issue and why the hearings are necessary.

Hagel said a law that was passed in 1978, The Foreign Intelligence Surveillance Act, has worked "very well."

The Foreign Intelligence Surveillance Act (FISA) provides a statutory framework for the use of electronic surveillance in the context of foreign intelligence gathering. The legislation was passed by Congress to strike a balance between national security interests and personal privacy rights.

"It holds any administration accountable," Hagel said. "The Congress is part of it. The courts are part of it. It plays out the way these kind of intelligence oversight issues should be handled."

He said the law was passed in 1978 because of abuse of domestic spying by the Nixon administration over Watergate and Vietnam.

This week Vice President Dick Cheney defended the spying program and called for "strong and robust" presidential powers.

Cheney -- a former member of congress, defense secretary and White House chief of staff under President Gerald Ford -- said executive authority has been eroding since the Watergate and Vietnam issues during the Nixon era.

"Every president, that we know of, has complied with the law (FISA)," Hagel said. "No president is above the law. We are a nation of laws and no president, majority leader, or chief justice of the Supreme Court can unilaterally or arbitrarily avoid a law or dismiss a law. If the vice president holds a different point of view, then he holds a different point of view."

Based on the facts that are out there concerning whether domestic spying abuses were taking place, Hagel said, there was a "breakdown."

"I take an oath of office to the Constitution," he said. "I don't take an oath of office to the vice president, a president or a political party. My obligation and responsibility are to the people I represent and the country I serve. I do what I think is right for the people I represent and the country I serve."

And part of that responsibility, Hagel said, is assuring that Americans' civil liberties are not violated or abused.

Hagel, referring to President Ronald Reagan, said people trusted him because he was not a "vitriolic person or one to impugn the motives of people who disagreed with him."

"Never did he do that," Hagel said. "There is no place for that in politics because it debases our system and our process. You can agree or disagree with your leaders and say whatever you like about your elected leaders and throw them out, but I do draw the line on the vilification and impugning of motives because someone disagrees with you."

He said the American people are "sick and fed up" with that type of politics.

"Cheney's poll numbers are very, very low," Hagel said. "This should be about elevating the debate and enhancing America and finding the solutions that we need to move forward. It doesn't help when you characterize people who disagree with you or threaten them or characterize them as unpatriotic or not caring about our people or our security. The American people see through that and it is beneath the dignity of this country."

The Associated Press contributed to this story.

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