Obama: America Not "What it Once Was"

Barack Obama is taking after his wife of talking down America:

“America is no longer what it could be, what it once was," Obama told her. "And I say to myself, I don’t want that future for my children.”

What American is he referring to - the pro-slavery America of the 1800s, the America pre-Civil Rights? I would love to hear his specifics about why he thinks America is no longer great. Or when it was actually great for that matter. (Apart from the typical Leftist view that "America is evil because of George Bush, etc,...)