Media commentary has suggested that recent Black Lives Matter (BLM) protests, particularly riots, drove voters, particularly Hispanic voters, away from Democratic candidate Joe Biden in the 2020 US presidential election. I test these hypotheses with county-level regression models of 2016-to-2020 swing towards the Democratic presidential candidate, using the presence and intensity of BLM non-riot protests and riots as regressors, controlling for state and many background demographic factors (population density, household size, racial composition, etc.). The models (generalized additive models) that control most aggressively for background factors find small and positive associations between BLM protests and Democratic swing: counties with non-riot BLM protests swung more towards Joe Biden by 0.2 percentage points, and counties with BLM-associated riots swung more towards Joe Biden by (a statistically insignificant) 0.1 percentage points. The extra BLM-protest swing was not statistically significantly different in counties with relatively many Hispanic voting-age citizens, although it was weaker in counties with relatively many Asian voting-age citizens. Inasmuch as these results reflect causal impacts of BLM protests, the protests enhanced the Democratic swing but were probably not electorally decisive. My most elaborate model suggests that a lack of BLM protests in 2020 would have flipped only one state: Biden might have narrowly lost Arizona.