Though there is, in the data, reason for some optimism, the more general picture contradicts the idea that the country underwent a racial reckoning. Last summer, as Black Americans turned their sorrow into action, attitudes — especially white attitudes — shifted from tacit support to outright opposition, a pattern familiar in American history. Whereas support for Black Lives Matter remains relatively high among racial and ethnic minorities, support among white Americans has proved both fickle and volatile... Like other racial groups, white Americans were more supportive of B.L.M. following Mr. Floyd’s murder. This sentiment, however, did not last long and, as with Republicans, support eventually plunged. This movement among Republicans and white Americans helps us understand why aggregate support for Black Lives Matter has waned since last summer. In both cases, the deterioration in support is noteworthy because we do not merely observe a return to pre-Floyd opinion levels. Rather, since last summer, Republicans and white people have actually become less supportive of Black Lives Matter than they were before the death of George Floyd — a trend that seems unlikely to reverse anytime soon.