In spring 2020, nearly every U.S. public school closed at the onset of the COVID-19 pandemic. Existing evidence suggests that local political partisanship was a better predictor of in-person instruction than COVID case and death rates in fall 2020. We replicate and extend these analyses using data collected over the entirety of the 2020-21 academic year. We affirm that local political partisanship was an important initial predictor of county-level in-person instruction rates. We also demonstrate that, under certain conditions, COVID case and death rates were meaningfully associated with initial rates of in-person instruction. We reveal that partisanship became less predictive--and prior average student achievement became more predictive--of in-person instruction as the school year continued. We then leverage data from two nationally representative surveys of Americans' attitudes toward education and identify an as-yet-undiscussed factor that predicts in-person instruction: public support for increasing teachers' salaries.