There are a few ways to define “racism.” Two I like have different implications on who is “racist” based on how we define the term. One racism is prejudice of a person based on his or her skin color. Another is the belief that some races are superior to others. In the first, most Americans would say they do not pre-judge, but it’s apparent that our culture subconsciously teaches this kind of racism. In the latter, it seems like the recent election made it a little more acceptable for people to say that “our” group is superior to the “other” group.
I don’t think there’s much use to the binary thought experiment, Is the US racist or not? I would rather we define racism and its acts and implications and look at the effects. If we define “a racist nation” as one where structural, systemic barriers exist for people of different “races,” then it’s hard to say the US doesn’t at a minimum carry its racist past into the present.