A “black swan event” is an unexpected event, after which experts and even laymen usually conclude: “It was bound to happen.” The label originated when Dutch explorer Willem de Vlamingh’s 1697 discovered black swans in Australia, when most people elsewhere assumed all swans were white.

Consider a couple of examples, with obvious consequences for Maine.

Last week included the 72nd anniversary of the black swan event known as Pearl Harbor.

The “greatest generation” who lived through that event and World War II can testify from personal experience about the costs of ignoring the clear warning signs of that attack.

Years earlier, Billy Mitchell’s private and particularly public attempts to get American powers to understand the future importance of air power led to his 1925 court marshal, at which he warned of the coming war with Japan and of the Pearl Harbor “surprise” attack.

But the powers that be ended Mitchell’s career, though he retained his hero status among air power advocates who would see his warnings come true. Many consider him to be the father of the U.S. Air Force.

Then, we had time not only to recover and with providential help — e.g., at Midway — defeat the Japanese in the Pacific and the Nazis in Europe.

Now we are courting an even more catastrophic black swan event by ignoring clear warnings of the existential threat from a natural or manmade electromagnetic pulse.

Maine has an opportunity to help avoid this one. We have clear warning of manmade and natural EMP events that pose an existential threat to America.

For example, consider the highaltitude EMP threat posed by an Iranian ballistic missile attack — which is not being countered by either our diplomatic or active defense policies:

— During the Cold War, the United States hardened its key military electronic systems to assure we could retaliate after a Soviet high-altitude EMP attack. After the Cold War, we learned Russia’s high-altitude tests were more extensive than ours, and they included high-altitude EMP in their attack plans.

— We continue to harden our strategic military systems — but not our civil critical infrastructure, especially the electric power grid upon which most other critical infrastructure depends.

— The congressionally mandated nonpartisan EMP Commission warned of the devastating consequences of such an attack in 2004, and in 2008 provided previously classified information to back up these conclusions.

The commission identified electric power grid vulnerabilities as critically important, deserving remediation immediately. Its chairman testified that, otherwise, most Americans could die within a year after a high-altitude EMP attack from starvation, disease and social collapse.

— Russia has shared nuclear and ballistic missile technology with China, North Korea and Iran — including help to North Korea’s efforts to maximize EMP.

Collaboration between Iran and North Korea has benefited both, ith help from Russia and China. Iran attended North Korean tests, which some believe were intended to demonstrate advanced designs for ballistic missile or satellite delivery to create highaltitude EMP effects.

— Iran’s extensive ballistic missile development has included tests that knowledgeable observers associate with a potential high-altitude EMP attack from a seagoing vessel, and its leaders have openly stated they could attack the United States from off our coasts.

— Last year, North Korea and Iran launched satellites that traveled over the South Polar regions, which could easily have been directed to optimize high-altitude EMP effects over the entire continental United States.

Recently, Iranian Naval Admiral Afshin Rezayee announced deployment of warships in the Atlantic Ocean; previously, Iranian officials said their ships can threaten U.S. coastal cities.

Once Iran mates nuclear weapons to its ballistic missiles, it can immediately threaten a devastating high-altitude EMP attack from bursts of an appropriately designed device a couple hundred miles over the United States, whether from a satellite or from a vessel off our coasts.

While Washington’s “powers that be” collectively fail “to provide for the common defense,” Maine has an opportunity to lead the nation in countering this well-known threat, which has been validated by numerous competent technical reviews.

Hardening costs are minimal by any reasonable measure. The Federal Energy Regulatory Commission, which understands the problem but doesn’t have the authority or resources to rectify the situation, estimated annual costs of less than a postage stamp per utility subscriber.

By protecting its portion of the electric power grid, Maine can ensure its citizens survive catastrophic collapse of the power grid induced by a severe solar storm, manmade EMP event, cyberattack or other cause. Such EMP protection will also mitigate all lesser hazards, such as blackouts induced by hurricanes and storms.

Maine state legislators should follow state Rep. Andrea Boland, D-Sanford, and others who almost unanimously passed historically important landmark legislation to protect Maine’s electric power grid, in spite of contrary lobbying efforts supported by the electric power industry.

HENRY F. COOPER was the first civilian director of the Strategic Defense Initiative, appointed by President George H.W. Bush in 1990.