For many years, I have advocated what I call Hannibal’s First Law of Leadership: “Never give an order that won’t be obeyed.” Hannibal’s Law recognizes that war is fought in the real world, and that a general who gives orders that aren’t obeyed won’t be a general for much longer.

We are now reaching that point in the United States when it comes to Covid-19 restrictions.

Exactly two months ago in March, I wrote about the importance of using behavior restrictions to slow the spread of the virus. I had been having a private debate with a friend (who cannot express his views on social media for fear of professional fallout) about the necessity for such restrictions.

“We agree on general principles, such as the belief that if the coronavirus were to cause only 60,000 American deaths over the next year, then we should end shelter in place. But we disagree on our predictions for the future. He thinks that shelter in place is a panic reaction, and that the coronavirus is no more dangerous than the flu, especially if you are young and healthy. I think that if we abandon shelter in place before we have better testing or effective treatments (in other words, before we are able to pull any other levers besides Behavior Change) we will overwhelm our healthcare system (which my healthcare professional friends tell me is already stretched to the breaking point) and cause hundreds of thousands of needless deaths, including many young and healthy people.”

Sadly, the United States is about to or has recently exceeded 100,000 Covid-19 deaths, with a death rate that remains over 1,000 per day. Testing has improved, but remains far from ubiquitous. Some treatments like remdesivir look promising, as do early vaccine trials, but we are still early in that process, and there is no magic bullet yet.

Despite the situation, many state and local governments are easing Covid-19 behavior restrictions, and the news is full of reports that beaches and other recreation spots are packed this Memorial Day holiday weekend.

I believe that crowds like the ones above are likely to lead to a second wave of infections, much as they did for the 1918 influenza pandemic. But I also believe that the best way to head off a second wave is not to insist, in ever more strident tones, that the only acceptable answer is strict and universal social distancing.

While it is true that strict social distancing would stop the spread of the virus, it is also true that it would violate Hannibal’s First Law.

A helpful analogy might be that of abstinence-only sex education. It is true that abstinence reduces the chances of pregnancy and sexually-transmitted diseases to zero. It is also true that it doesn’t work, because it violates Hannibal’s First Law.

During the George W. Bush administration, the Department of Health and Human Services funded a study of the effectiveness of abstinence-only sex education. The conclusion?

“The impact results from the four selected programs show no impacts on rates of sexual abstinence. About half of all study youth had remained abstinent at the time of the final follow-up survey, and program and
control group youth had similar rates of sexual abstinence. Moreover, the average age at
first sexual intercourse and the number of sexual partners were almost identical for program
and control youth.”

More problematically, the children in those programs were less likely to report that condom usage could protect against STDs, and more likely to believe that condoms were never effective against STDs.

The key to effectively using behavior restrictions to combat the spread of Covid-19 is to use the best science and evidence available to craft a set of restrictions that both A) reduce transmission and B) will be broadly obeyed.

Fortunately, we have learned some important things in the past two months:

• Wearing masks significantly decreases the rate of infections
• Sunlight and humidity decrease the half-life of the virus on surfaces
• The virus seems to spread the most from prolonged proximity to an infected person, generally indoors
• The deadliness of the virus varies greatly by age; nearly 74% of those who died in New York City were senior citizens (65+), and another 22% were in the 45-64 age category (a statistic that is not that comforting to this 45-year-old)

This suggests a number of ways to more precisely target behavioral restrictions.

First, mask-wearing should be mandatory. It is a low-cost intervention that has been proven to work in other parts of the world.

Second, the elderly and other vulnerable groups should be encouraged to maintain a stricter level of physical distancing. I do not believe that this needs to be mandatory, since there is no evidence that the vulnerable are more likely to transmit the virus; if they choose to take on additional risk to themselves without increasing the risk to others, then that is a personal choice. However, the corollary is that nursing homes and other senior communities should have much tighter behavior restrictions, since the consequences of infection are so much greater.

Third, we should recognize that different social activities carry different risks, and restrict accordingly. Outdoor recreation like hiking is low-risk, and should be allowed (with mask-wearing and social distancing). Indoor activities like attending a church service are high-risk, and should be restricted. If a church wishes to hold services, it could do so outdoors to reduce the risks of transmission.

The point is to be guided by science and evidence, and to recognize that policies need to obey Hannibal’s First Law, whether they are social distancing during a pandemic or sex education in schools.

Had policy makers followed Hannibal’s First Law, and begun targeted easing of behavior restrictions as new evidence emerged, we would likely be seeing less open defiance and flouting of the restrictions that really make a difference.

The fact that many of those who are loudest in defying governments and calling for a “re-opening” of America are A) acting childish and B) following the advice of Russian bots is maddening, but irrelevant. The virus doesn’t care about its host’s opinions, just that it can spread.

Now is not the time for Covid-19 fundamentalism. We shouldn’t insist on either a strict and universal lockdown, or a complete lifting of restrictions. We should all be focused on the same goal: Limiting the spread of Covid-19 to reduce pointless deaths and suffering until medical science provides better treatments and vaccines.