Electromagnetic pulse (EMP) was discovered—or perhaps better said, the dangerous and destructive side-effects of EMP were discovered—quite by accident in 1962, after a nuclear warhead was test-detonated 248 miles above Johnston Island. Immediately after the blast, telephone lines, power lines and electrical systems shorted out in Hawaii—900 miles away from the test. The military soon began to harden new weapons systems against the effects of EMP. But in the half-century since, America finds itself less equipped and less prepared for a high-altitude EMP attack, even as the nation has become more dependent on the electronic devices that an EMP event would destroy.

As recently detailed in the journal of the Association of Former Intelligence Officers, radios and TVs, heating and air conditioning units, cellphones, computers, landline phones, most cars built after 1980, sewer and water pumps, and vast swaths of the power grid would cease to work after an EMP event. And they would be out of service for many weeks or months, throwing our technology-dependent economy society back to the 1800s.

Yet Peter Pry, who served on the Congressional EMP Commission, noted in 2015, “The White House and the Congress have done nothing to protect the electric grid from a long-term blackout,” the effects of which “could kill up to nine in 10 Americans by starvation and societal collapse.”

Pry explains that “The likelihood of a nuclear EMP attack is unknown but increasing with the proliferation of technology for missiles and nuclear weapons,” adding: “The military doctrines of Russia, China, North Korea and Iran describe a revolutionary new kind of warfare that would use cyberattacks and physical sabotage, combined and coordinated with EMP attack, to black out the national electric grid and crash the other critical infrastructures…For the first time in history, failed states such as Iran or North Korea or terrorists could use a blackout war to destroy the most successful societies on earth.”

To be sure, Russia and China are responsive to deterrence and the threat of overwhelming retaliation. But a paranoid Pyongyang and a terrorist Tehran may not be.

“We have data indicating that the Iranians have launched their versions of Scuds off of the Caspian Sea—not from land, but from the sea—and launched them over land,” William Graham explained in a recent Forbes interview. Graham, who has worked with the highest levels of the federal government and the military on EMP preparedness since the 1962 event, chaired the Congressional EMP Commission.  “We’ve also seen them launch missiles that have gone up and apparently exploded near their highest altitude—when you put those two ideas together—that is an EMP attack.” Indeed, the Iranian military has contemplated such an attack against the U.S.

According to Pry, “North Korea has actually practiced this against the United States.”Thus, Graham and other EMP experts from the Foundation for Resilient Societies warned in a 2013 letter to President Barack Obama, “A high altitude nuclear EMP attack from North Korea is an imminent threat to the United States.”

The threat isn’t limited to the world’s rogues: Solar flares can trigger a “geomagnetic storm” that can have the same effect as a high-altitude EMP blast. “The last such flare—known as the Carrington Event—happened in 1859, frying telegraph lines around the planet,” The Atlantic magazine reports. Even a non-hostile event like this would affect 130 million people and cost $2 trillion today, according to The Atlantic’s analysis.

These threats and possibilities explain why the Pentagon is relocating key communications assets to Cheyenne Mountain and pouring nearly $1 billion into NORAD’s Cold War bunker. “Since 2013, the Pentagon has awarded contracts worth more than $850 million for work related to Cheyenne Mountain,” DefenseOne reports. “Because of the very nature of the way that Cheyenne Mountain is built, it’s EMP-hardened,” explains Adm. William Gortney, former commander of NORTHCOM and NORAD.

Learning

This is no time for panic; it is time for action.

The good news is this: The United States can—if it summons the will—prepare for and guard against the EMP threat.

Toward that end, Graham and his colleagues urged Obama to pursue “emergency deployment of cost-effective missile defense systems” to provide a first line of defense against North Korea’s and Iran’s missile capabilities.

In the medium term, they called for “protection of electric-grid control rooms at regional balancing authorities” and protection of “critical Extra High Voltage transformers” across the country.

In the long-term, they called on Washington to ensure that “all high-priority critical infrastructures when upgraded or replaced…be subject to nuclear EMP-protection standard.”

In a similar vein, the EMP Coalition—with former House Speaker Newt Gingrich leading the way—has called on government and industry to work together to harden the electrical grid with the equivalent of large-scale surge protectors at key points in the grid. So-called “Faraday Cages”—boxes that absorb electrical current—could be installed at key junctures. In addition, as The Atlantic reports, government and industry need to have replacement parts, such as industrial-scale transformers, at the ready. These can take years to fabricate and field.

Legislation in two different congresses and a blue-ribbon commission that worked from 2001 to 2008 tried to push these sorts of measures. But nothing has become law to date. That may be due to cost—estimates for hardening the grid against EMP attack and/or geomagnetic storms range up to $20 billion—or old-fashioned American complacency.

We should learn from how previous generations of Americans responded to major threats. George Washington urged Congress to choose “preparation and vigor” over complacency, and to summon the will “to do what our abilities and the circumstance of our finance may well justify.” Dwight Eisenhowercited continuity and national security in rallying support for the interstate highway system: “In case of an atomic attack on our key cities, the road net must permit quick evacuation of target areas, mobilization of defense forces and maintenance of every essential economic function.” Ronald Reagan established—and his administration rehearsed—detailed continuity-of-government contingency plans, in the event of a Soviet attack.

These leaders understood the importance of preparedness and resiliency—and the need for action. Twenty-billion dollars seems a small price to pay to protect and secure something on which our entire way of life depends.