...although they can and do host receptions and other more social activities for them.

Foreign policy and substantive dealings with foreign governments are exclusively reserved for the federal government. Otherwise, the Vermonters would have made their own treaties and agreements with Canada a long time ago, because that's how Vermonters are.

The Office of the Governor of Alaska can deal with foreign business people whose businesses are operating in their states, and with embassy personnel who are representing the interests of their nationals within the state, but this is as true of the Office of the Governor of Nebraska. And of the Office of the Mayor of New York City, where it's more likely.

If Palin had had substantial dealings with any foreign dignitary or official as part of her duties as Governor, don't you think the McCain campaign would have highlighted this, possibly with a flourish of trumpets, by now?