Updated: 12:12 p.m.

As the White House pushed its case for military intervention in Libya a day before the president plans to address the nation, some of Capitol Hill’s biggest voices on the subject took to the airwaves Sunday to buoy their own positions.

Sen. John McCain called the U.S. and NATO military efforts in Libya “a golden opportunity” to help democracy and freedom in the Arab world. If the United States had not gotten involved against Libyan leader Moammar Gaddafi, the Arizona Republican said on “Fox News Sunday,” it would have sent a signal that “it’s OK to massacre your own people to stay in power.”

Sen. Joe Lieberman (I-Conn.), who also appeared on “Fox News Sunday,” called the situation in the Middle East “remarkable” because people of the Arab world are saying: “We want democracy. We want freedom.”

McCain compared the recent wave of democratic uprisings in the Middle East to the fall of the Ottoman Empire or the collapse of the Soviet Union. These are “historic times of enormous opportunity and proportions,” he said.

Although Lieberman conceded that the diplomatic rhetoric has been “confusing,” he said the United States has “taken a side in Libya, and it’s the right side.” McCain said he hoped the president will clarify his policy during his address to the nation Monday evening.

Lieberman also said he would support a Libya-like military intervention in Syria, where a government reform movement is spreading across the nation, if President Bashar Assad “turns his weapons on his people” as Gaddafi did. “There’s a precedent now the world community has set” with Libya, Lieberman added.

Syrian security forces fired on protesters Friday, killing at least 14 people, the Washington Post reported. Assad pulled back security forces from the city of Daraa, the center of unrest, and released hundreds of political protesters from military prison the next day in an apparent attempt to ease the tensions, the newspaper reported.

Senate Foreign Relations ranking member Dick Lugar, who has criticized the administration for joining international partners in enforcing a no-fly zone over Libya without Congressional approval, framed the conflict as a civil war that the United States should stay out of.

“I don’t believe we should be engaged in the Libyan civil war,” the Indiana Republican said on NBC’s “Meet the Press.” “I believe the Libyans are going to have to work that out. The fact is that we don’t have particular ties with anybody in the Libyan picture, and we will have to at least adjust to whatever that outcome may be. As far as we’re concerned, Secretary [of Defense Robert] Gates has said it’s not of vital interest to the United States, American interests are not at stake, and we … already have done much more than our part with regard to the no-fly zone, with regard to European friends.”

He also warned about the drain on the United States’ resources, considering “the huge economic problems we have.”

“Estimates are that about $1 billion has already been spent on an undeclared war in Libya; some would say only hundreds of millions and that that will diminish in the days ahead,” Lugar said. “But who knows how long this goes on? And furthermore, who has really budgeted for Libya at all?”

Gates made the Sunday news show rounds with Secretary of State Hillary Rodham Clinton, appearing on CBS’ “Face the Nation,” ABC’s “This Week” and “Meet the Press.” (Chris Wallace, host of “Fox News Sunday,” noted on his program that the administration declined to send Gates and Clinton to his show, despite requests.)

Clinton was asked on “This Week” to reconcile the Libya mission with past statements that she and President Barack Obama made as Senators about the need for Congressional approval of military attacks in situations that do not involve stopping actual or imminent threats to the United States.

Speaking about the hypothetical use of force against Iran in 2007, then-Sen. Clinton said, “If the administration believed that any, any use of force against Iran is necessary, the president must come to Congress to seek that authority.”

On Sunday, the secretary of State said the Obama White House welcomes Congressional support.

“But I don’t think that this kind of internationally authorized intervention, where we are one of a number of countries participating to enforce a humanitarian mission, is the kind of unilateral action that either I or President Obama were speaking of several years ago,” Clinton said. “I think that this had a limited time frame, a very clearly defined mission, which we are in the process of fulfilling.”

She referenced a “constant flow of information both to Members and staff” during her appearance on “Meet the Press.”

Senate Armed Services Chairman Carl Levin expressed support for the U.S. role in Libya during an interview on CNN’s “State of the Union.” The Michigan Democrat’s committee plans to hold hearings Tuesday with the NATO commander about Libya.

Levin emphasized that the goal is not to unseat Gaddafi using military force. He said there are other ways to do that, specifically that the people remove him from power or seriously weaken him so that he cannot hurt civilians. He also said the United States must work in conjunction with its international partners and must not make unilateral decisions.

The mission in Libya is very different from the military action in Iraq, which did not have U.N. support, Levin said. “There was no U.N. support in Iraq, and it made a big difference,” he added.

Melanie Starkey contributed to this report.