Talk to the experts in psychometrics, and they'll tell you that this is still an open question. It was a plurality (not majority or consensus) view in psychometrics that there was some genetic influence (beyond the obvious, e.g. black skin attracting discrimination, etc) back in 1984, but since then there has been other work that changes the picture, e.g. that of James Flynn, Will Dickens, and Richard Nisbett. It's unclear what a poll done today would reveal.

The experiments that would give huge likelihood ratios just haven't been done. Transracial adoption studies have been very few, flawed in design, and delivered conflicting results. And so far, genomics has revealed almost nothing positive about the genetic architecture of intelligence in any ethnicity, much less differences between ethnicities. Cheap genome sequencing may well bring answers there in the next 5-7 years, pinning down this debate with utterly overwhelming evidence, but it hasn't done so yet.