Before revision:  Our counterfactual experiments indicate that removing all policies would have lead to 30 to 200 times more additional cases by late May.
After revision:  Our counterfactual experiments suggest that nationally mandating face masks for employees on April 1st could have reduced the growth rate of cases and deaths by more than 10 percentage points in late April, and could have led to as much as 17 to 200 times more additional cases by late May.