WASHINGTON — In her first interview since becoming the Republican nominee for vice president, Alaska Gov. Sarah Palin said the U.S. might have to go to war with Russia under certain circumstances and she rejected questions about her readiness for office.

Palin, who returned to Alaska to see her oldest son off to Iraq yesterday, sat down with ABC World News anchor Charlie Gibson for a series of interviews. The first interview aired on World News and Nightline and the final clips will air today on Good Morning America, World News and a special edition of 20/20.

Like Sen. John McCain, the Republican presidential nominee, Palin has taken a hard line on Russian aggression.

When asked if, under the NATO Treaty, the U.S. would need to go to war with Russia if it invades Georgia again, she said, "perhaps so.

"I mean, that is the agreement when you are a NATO ally, is if another country is attacked, you're going to be expected to be called upon and help," Palin said. "For Russia to have exerted such pressure in terms of invading a smaller democratic country, unprovoked, is unacceptable."

Adding that she had recently spoken by telephone with Georgian President Mikhail Saaka-shvili, she said: "We have got to keep our eyes on Russia."

Palin said she favored including the former Soviet Republics of Georgia and Ukraine in NATO and that the situation does not necessarily have to result in war.

"It doesn't have to lead to war and it doesn't have to lead, as I said, to a Cold War, but economic sanctions, diplomatic pressure, again, counting on our allies to help us do that in this mission of keeping our eye on Russia and Putin and some of his desire to control and to control much more than smaller democratic countries," she said.

Palin, the mother of five, has faced scrutiny and criticism for her short resume as a governor of just 20 months. But voters have responded to her on the stump, and McCain has seen his crowds, coffers and poll numbers swell in the past two weeks.

She brushed off questions about her readiness to assume the vice presidency when asked, "Can you look the country in the eye and say I have the experience and I have the ability to be not just vice president but perhaps president of the United States?"

"I do, Charlie," she said. "And on Jan. 20 when John McCain and I are sworn in if we are so privileged to be elected to serve this country, we'll be ready. I'm ready."

Over the course of the interview, Palin expressed strong support for Israel's right to defend itself, expressed no reservations about possibly crossing into Pakistan without its government's approval to pursue terrorists in the mountainous Waziristan region, and seemed unfamiliar with the "Bush Doctrine," which says the United States does not need to wait to be attacked before going to war.

Asked if she had ever traveled out of the country, she said she has traveled to Canada and Mexico, as well as to visit troops in Kuwait and Germany. She said she has never met a foreign head of state, but noted other vice presidential candidates in history had not, either.

"I don't think we can second guess what Israel feels it has to do to secure its nation," she said when asked how she would respond if Israel decided to obliterate Iran's nuclear weapons facility.

Questioned about entering Pakistan to pursue terrorists, she said, "I believe that America has to exercise all options in order to stop the terrorists who are hell bent on destroying America and our allies. We have got to have all options out there on the table."

Gibson also read Palin a comment she had made in church about "our national leaders are sending U.S. soldiers on a task that is from God" — and asked if she viewed the United States as fighting a holy war.

"I would never presume to know God's will or to speak God's words," Palin said, saying that she was recalling Abraham Lincoln's own words.