Crushed by COVID-19, rural red states finally start to mandate masks. It may be too little, too late.

Earlier this week, Iowa’s Republican Gov. Kim Reynolds made national news when she reluctantly set aside her long-standing opposition to mask mandates and finally agreed to issue one in a state with a large rural population where COVID-19 is spreading at an "exponential and unyielding” rate.

“I don’t want to do this,” said Reynolds, who for months dismissed mask requirements as an unenforceable “feel-good” measure that she was “not going to” implement. “[But] if Iowans don’t buy into this, we lose. The cost in human life will be high.”

Reynold’s abrupt reversal, which coincided with similar U-turns in Montana and North Dakota, was largely seen as a welcome sign that red states are now accepting what blue states (and scientists) have known since summer: Mandating masks leads to more mask-wearing, and more mask-wearing leads to less coronavirus.

According to a new study on the impact of St. Louis’s July 3 mask mandate, for instance, average daily COVID-19 case growth in St. Louis three weeks after the ordinance went into effect was 44 percent lower than in neighboring counties where masks were not required. Twelve weeks later, case growth in St. Louis was still 40 percent lower.

Put another way, 13 of the 17 states currently struggling with the highest COVID-19 positivity rates are also states that don’t mandate masks or that just issued statewide mandates this month.

“The data shows that … when you put in a mask mandate, more than 80 percent of that specific population [starts] following it,” explained Dr. Enbal Shacham of St. Louis University, the lead author of the Missouri mask study. “It's going to have a reduction.”...

iowa’s new mask mandate should serve as a warning to the rest of the country about how not to craft a mask mandate. Don’t riddle it with loopholes. Don’t undermine it with mixed messages. And most of all, don’t issue it only after hospitals — especially rural hospitals — start to reach capacity. ...