A November 9 VOX article advocating state mask mandates compares monthly cases per 100,000 with states the do have such a mandate (shown in Gold) such as Wisconsin, Utah and Arizona with those that do not have a mask mandate (shown in dark red) such as Kansas, South Carolina and Florida.
The reader is supposed to infer that mask mandates made made Wisconsin COVID-safer compared with, say, Florida, though that's obviously untrue. But the correlation would be suspect in any case, because (1) outbreaks could lead to mask mandates being enacted in panic regardless of their efficacy, and (2) states without statewide mask mandates often have county or city mandates.
My county in Florida mandates masks indoors, so the state numbers are misleading. Even self-centered people living in hot spots don't need to be ordered to do whatever they can to avoid catching disease, though only medical-quality masks might help to do that.
An October 23 Washington Post article offered "A powerful argument for wearing a mask, in visual form." It compared the percentage of people who said they usually wore masks on October 19 with the percentage who said they knew someone who had experienced symptoms related to COVID-19 (such as coughing or fever).
This is not a powerful argument for state or national mandates to wear a mask, because it shows mask usage is at least as high in states with no mask mandate (83% in FL, 86% in AZ, 87% in NH) as it is in states that ostensibly require masks (75% in OH, 78% in MT, 79% in KS, 81% in IN).
Also, knowing someone with recent symptoms was bound to be (and is) highest in Midwestern and Plains states that were only recently hard-hit by the virus for the first time - including those with mask mandates such as Wisconsin (35%) and Montana (39%) and those without (such as 33% in Alaska).