A poll released on Wednesday (Thursday AEST) found that Democrats were 45 percentage points more likely to say they wore a mask in public than Republicans.
This divide is reflected in the behaviour of the parties’ respective political leaders. President Donald Trump wore safety glasses but not a mask when touring a mask factory in Arizona this week. Vice-President Mike Pence declined to wear one during a recent visit to the Mayo Clinic in Minnesota.
Meanwhile, Democratic House Speaker Nancy Pelosi regularly wears a mask in the US Capitol building – often colour co-ordinating it with her outfit.
Some Americans have embraced mask-wearing as way to express solidarity with essential workers and to show they are taking the pandemic seriously. Online tools allow people to easily add a surgical mask to their social media profile pictures, and many have done so. Reporters on television stations like CNN increasingly wear masks for their live crosses, even if there is no-one else around.
The main health rationale for wearing a mask is preventing the spread of the virus to others, rather than protecting the person wearing the mask. This appears to connect more with those who have a collectivist world view than people who strongly believe in individualism and personal responsibility.
Cheryl Chumley, a columnist for the conservative Washington Times newspaper, argued that mask rules belonged in a “communist, dictatorial, tyrannical kind of country”.
“This seems a blatant violation of an individual’s right to choose – of an individual’s right to self-govern,” she wrote.
The partisan divide is not absolute. Maryland’s Republican Governor Larry Hogan was one of the first state leaders to introduce mask wearing rules. But he is a moderate in a state that leans to the left.
Ohio’s Republican Governor Mike DeWine, whose state is more rural and conservative, encountered more resistance when he tried to implement an order requiring people to wear masks in stores. He changed his mind after a voter backlash, saying masks would only be recommended rather than mandated.
“It became clear to me that that was just a bridge too far,” he said. “People were not going to accept the government telling them what to do.”
Nino Vitale, a Republican politician in Ohio, said he was opposed to wearing a mask because he believed it dishonours God.
“This is the greatest nation on earth founded on Judeo-Christian principles,” Vitale wrote on Facebook.
“One of those principles is that we are all created in the image and likeness of God. That image is seen the most by our face. I will not wear a mask. That’s the image of God right there, and I want to see it in my brothers and sisters.”
Michigan’s Democratic Governor Gretchen Whitmer has issued a mandate requiring people to wear masks in public enclosed spaces, and wears a mask at her press conferences.
The issue turned deadly in her state when a Family Dollar security guard in Flint was shot dead after telling a customer that her child had to wear a mask inside the store.
It wasn’t a total success. On day one police issued 652 warnings to people not wearing masks, leading the city manager to warn that he would close the parks again unless more people complied with the rules.
Matthew Knott is North America correspondent for The Sydney Morning Herald and The Age.