Liz Umlas, sr. research analyst at KLD (background on Liz is here) offers some additional commentary on Warren Buffett and the Sudan issue:
"I read your 2/23 post on 'Warren, Charlie and Bill...' with interest. This statement stuck out for me: 'For Warren Buffett to be a social investor he doesn't have to do what I think is right, or what anyone else thinks is right. He has to do what he thinks is right.'
"What he believes, in this case, is that (a) PetroChina is not involved in Sudan, and (b) Berkshire's divestment from PetroChina would not change the Sudanese government's actions (his comments are here).
"Andrew Leonard in Salon.com, also on 2/23, knocks down Buffett's first point. He notes the extensive connections between PetroChina and CNPC, the parent company that has operations in Sudan, and concludes, 'To declare, as Berkshire does, that a subsidiary has no ability to control the policies of the parent, when the two entities are run by the exact same people, is an exercise in specious obfuscation.'
"I would have to agree with Mr. Leonard.
"Regarding Buffett's second point, that Berkshire's investments - or divestment - would have no effect on the situation at hand; well, this obviously goes against a fundamental tenet of social investing - the use of investment to bring about positive social change. As you point out, Buffett and Gates are among the world's richest people, and if any individual investor is going to have a shot at influencing companies in which they invest, I'd hazard a guess that Buffett/Berkshire and the Gates Foundation qualify.
"So it's hard to see how Buffett is a social investor. It seems that what he thinks is "right" is maximizing returns regardless of the social consequences, whether that means investing in tobacco (you point out Berkshire's past ownership of such), or in companies that do business with the government of Sudan.