Obama, Gay Marriage and Evolution

Left Coast Rebel  "White House press secretary Jay Carney, when questioned if Biden's remarks signaled a change in Obama's position, repeatedly told the press that Obama's views were "evolving". When pressed if "evolving" meant "changing his position", Carney mustered his best double speak, twisted himself into a pretzel worthy of the name, and mumbled something about evolving "not necessarily" meaning change. Come again? 
Let me quote three of the first four words Wikipedia uses to describe evolution: "Evolution is...change...". The Random House Dictionary lists "change" as one of the synonyms for evolution. Some speculate that Obama wants to signal his liberal friends that he will be "more flexible" after the election in pursuing a more left leaning position, but that he cannot afford to offend any of his more conservative, churchgoing base.