"(E)xpanding NATO would be the most fateful error of American policy in the entire post-cold war era. Such a decision may be expected to inflame the nationalistic, anti-Western and militaristic tendencies in Russian opinion; to have an adverse effect on the development of Russian democracy; to restore the atmosphere of the cold war to East-West relations, and to impel Russian foreign policy in directions decidedly not to our liking," – George Kennan, as cited by Greg Djerejian.
When you read Greg’s post, you begin to understand how great a gamble a McCain administration would be. Think: Bush with less caution.