Unclear that it was "the U.S." who overpromised to Georgia. More likely it was John McCain's chief foreign policy adviser, Randy Scheunemann. He's been a paid lobbyist for Georgia in the U.S. for over 3 years.
But whoever it was, there's always the issue with any Russian equity of ownership risk. This is particularly a concern with natural resources. We know there's value in there, but we don't know that that value will go to shareholders and not to (a) the government, whether through expropriation or punitive taxes or (b) cronies somewhere.
Russian Oil Is Worth the Risk [View article]
But whoever it was, there's always the issue with any Russian equity of ownership risk. This is particularly a concern with natural resources. We know there's value in there, but we don't know that that value will go to shareholders and not to (a) the government, whether through expropriation or punitive taxes or (b) cronies somewhere.