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 and teachers' union strength were better predictors of fall 2020 school re-opening status than COVID case and death rates. We replicate and extend these analyses using data collected over the entirety of the 2020-21 academic year. We reaffirm that local political partisanship and teachers' union strength were reliable predictors of school re-opening decisions. We also demonstrate that Covid case and death rates were meaningfully associated with initial rates of in-person instruction. We show that all three factors--COVID, partisanship, and teachers' unions--became less 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.