Politics have been getting in the way of Americans broadly adopting a crucial preventative health measure: Wearing a mask in public to curb the spread of COVID-19. Now, though, the experts that have been urging that practice have an enormously powerful ally in Walmart Inc.

The big-box retailing giant said Wednesday it would require customers at its eponymous stores and Sam’s Club chain to wear face coverings. While some 65 per cent of its locations were already doing this to comply with local regulations, it will make it mandatory at all stores nationwide beginning July 20.  

Walmart does not get any credit for leading the industry on this, given that Costco Wholesale Corp., Best Buy Co. and Starbucks Corp. had earlier moved in this direction.

Still, it was certainly the right thing to do because it will go a long way toward protecting its customers and the 1.5 million employees of its U.S. stores. And because of Walmart’s ubiquity and its outsize influence in American shopping, its embrace of the policy could be a hugely important step toward getting mask-wearing to be a routine behavior in all sorts of public domains. 

Walmart stores are often located in rural areas, which have only recently started to see a surge in COVID-19 cases and are likely to be brimming with voters who cast a ballot for President Donald Trump and have taken note of his dismissiveness of masks.

In many of these places, Walmart is one of consumers’ only options for buying household essentials. If a grocery trip can normalize mask-wearing for these people, that’s a win for everyone’s health.

Walmart also has plenty of establishments in states such as Florida and Texas where cases are surging and governors have been reticent to take aggressive action to stop it. In those places, the chain is effectively stepping in to curb the spread of COVID-19 where lawmakers have failed. 

As the country’s largest retailer, Walmart’s move also gives cover to smaller chains to require mask-wearing. I’m sure many mom-and-pop retailers have seen the viral videos of shoppers throwing tantrums at store employees over mask policies and are loathe to have such fire-breathing scenes happen in their establishments.

But if mighty Walmart is making customers do this, these stores should feel emboldened to make the choice that is best for public health.

In fact, within hours of Walmart’s announcement, industry trade group the National Retail Federation issued a press release urging all retailers to require customers to wear masks nationwide. The group said it hoped Walmart’s move was “a tipping point” on this issue.

 It remains to be seen how easily and successfully Walmart can enforce this policy. The company says it will install “health ambassadors” at each store, workers positioned near the entrance who will responsible for reminding visitors of the mask requirement.

That may be a delicate task, especially at first. But, with any luck, Walmart’s move will create an industrywide norm that will soon make the act of wearing a mask mundane and apolitical. 

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Sarah Halzack is a Bloomberg Opinion columnist covering the consumer and retail industries. She was previously a national retail reporter for the Washington Post.