The scientific guidance on wearing masks to slow the spread of COVID-19 has become stronger in recent weeks, but Gov, Mike Dunleavy won’t take the single most effective action open to him—issue a state mandate to require masks in businesses.

More than 200 Alaska health care professionals have asked Dunleavy to require masks to slow the spread of the disease, protect vulnerable people and help the Alaska economy recover. More people will feel safe in venturing into businesses if this precaution is taken.

“The takeaway is this: a sick person wearing a mask will spread fewer viral particles. A healthy person wearing a mask will have some protection from sick people around them. The combination of both people wearing masks provides the greatest amount of protection,” the letter states.

If Dr. Anne Zink worked in a private practice, I’m confident she would have added her name to the letter. She should give her opinion on whether a mandate is a good idea at the next Dunleavy public relations show.

The Centers for Disease Control, the World Health Organization and the State of Alaska recommend wearing masks, but tens of thousands of Alaskans are ignoring the advice, assuming that because it is not a mandate that wearing a mask isn’t really important.

Trump and the Republican Party have made wearing masks into a political issue. Noisemaker Suzanne Downing claims she did a “deep dive” into the letter to Dunleavy, concluding that the health care professionals are backers of the recall or dupes who are trying to embarrass Dunleavy.

More than 55 percent of the signatures are from people Deep Dive Downing couldn’t find on the recall list, but failing to highlight that statistic is a way of masking her bogus argument.

I’ll put my trust in the Alaska health care professionals, who make a solid case for wearing face coverings and slowing the spread of the disease.

Before the outrage machine was cranked up with nonsense about martial law and the freedom to allow unfettered coughing, the Dunleavy administration approved a sensible policy in late April that in nonessential businesses, customers and employees had to wear masks.

Then the state abandoned that rule in favor of no rule, a clear signal that the state did not consider wearing masks as important.

Dunleavy hasn’t responded to the letter, but he mentioned Wednesday that the state would get “better outcomes” by not making masks mandatory. He’s wrong about that.

“We’ll keep an eye on this and see what happens with our case counts and numbers,” Dunleavy said last week, before the health care professionals asked him to take action.

The case counts and numbers are going up, as Dunleavy keeps an eye on them.