He used unethical means (pretexting) to obtain information from the Heartland Institute, which has been a consistent opponent of his in the climate change debate.
During one televised debate, Mr Bernstein fumbled a question posed by his opponent about water rights in northern Nevada, and seemed unable to name the counties involved in the dispute.
In other words, Obama was headed into adebate where his premises would not be challenged, his opponent clearly does not have the same level of expertise and could only attack him on peccadilloes.