I do NOT mean Gov. Palin is a no-brainer.

from Stan's link above

Palin told interviewer Charles Gibson of ABC News that Georgia should be granted membership of NATO. When pressed on whether this would mean that the U.S. would be obliged to defend Georgia if Russian troops went into the country again, she replied, "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."

"What I think is that smaller democratic countries that are invaded by a larger power is something for us to be vigilant against," Palin added. "We have got to show the support, in this case, for Georgia."
So, what does the NATO Treaty say:

Article 5

The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.

Any such armed attack and all measures taken as a result thereof shall immediately be reported to the Security Council. Such measures shall be terminated when the Security Council has taken the measures necessary to restore and maintain international peace and security .
http://www.nato.int/docu/basictxt/treaty.htm

Now, admittedly, we can find weasel-words in Article 5 - "such action as it deems necessary". So, a NATO state could find "the use of armed force" to be "not necessary". A warning to little countries ?

Bottom line: Gov. Palin's "Perhaps" was justified by the treaty's weasel-words; and the rest of her answer was substantially accurate as to NATO obligations.

PS 1: My dog is not in this political fight - I support neither ticket - but, fair is fair.

PS 2: Article 5 provides the implications for Europe and the US.