Over the years, we have been struck repeatedly by how often President Obama is wrong. Not how often we disagree with him, but how often he is just plain wrong, on matters of history, science and so on. Obama has a blithe willingness to assert false propositions of fact, apparently without fear of correction. I suppose that is because the Democratic press has little incentive to point out his errors. Let’s note two instances from a single town hall appearance in South Carolina yesterday. The first related to climate. Obama, while defending his Keystone veto, said: The pattern overall is...