If we signed a treaty, then we obligated to the terms of that treaty.
Which brings up the question, did we think this through when we signed the treaty (with Poland)?
Lets not forget that Obama supported the Nato expansion to GA. Of course, back then, it was just a warm fuzzy that didn't seem as if it would mean a whole lot.
And war is more likely if we pick and choose among our commitments. The same people that insist we do something about Dafur would not support the necessary military action that doing something entails.
If you make a promise, you keep the promise. Especially when dealing with dictators. Because if they think they can get away with it, they will push and push and push until you are at the edge.
When the English made a promise to the Czechs without having the means to back it up, they made the blitz a certainty.
So the essential thing here is, don't say you are going to do something unless you intend to back it up. Palin was making the point we have made promises. Our security depends on us fulfilling them. Of course, Palin's husband seems to be one of the Buchanan brigades, so I think Palin herself probably thinks the commitments were probably a bad ides in the first place, but once made, they are in concrete.