The most serious threat to the United States is not a physical terrorist attack, but a cyber-related one. In Washington, you can probably count on one hand the issues that both Republicans and Democrats can agree on — this is certainly one of them. The inevitability of such a catastrophic event and the destruction that it could cause is a nightmarish scenario that without a doubt keeps our elected officials and military leaders awake at night. The question isn't "If ...?" but "When ...?"

Imagine life for one day, or even one hour, without computers or the Internet. Each day, hundreds of millions of Americans rely on their computers to pay bills, manage their finances and shop. Our transportation system relies on computers to run our subway and railroad systems. The military uses computers to go to war or to launch missiles. Almost everything we do as a society is managed by a computer. We are living in a digital society.

Leaders in Washington imagine two catastrophic events with devastating consequences.

The first is a cyberattack on the U.S. electric grid. According to a 2015 report released by the University of Cambridge Centre for Risk Studies, the effects would be instantaneous and unimaginable, causing a $1 trillion impact on our economy and resulting in more than $70 billion in insurance claims. Imagine a severe blackout affecting the Midwest or Northeast, and impacting major U.S cities like Chicago or New York. The result, according to the report, would leave more than 93 million Americans in complete darkness.

The second scenario is a cyberattack in Manhattan, the financial epicenter of the world. One successful attack would cripple the world economy. The U.S. economy is $17 trillion. In Manhattan alone, two banks transfer $7 trillion each day. Imagine the complete devastation if a cyber terrorist was successful at interrupting these financial transactions.

The second scenario is one that kept retired Navy Adm. Mike McConnell awake at night when he was the director of national intelligence. As Adm. McConnell would recount several years later, in closed-door meetings with then-President George W. Bush and later President Barack Obama, he would refer back to the latter situation as the ultimate nightmare scenario.

The Pentagon records on average 100,000 cyber intrusions each day, or 30 million per year. Most of the attempts to infiltrate and expose our military computer network are coming from China – but Russia, Pakistan and Iran are all trying as well. Despite implementing robust cybersecurity systems, the task presents a huge burden on our civilian and military leaders. All it takes is one successful hack – a fact that civilian and military leaders are reminded of every single day.

According to McConnell, a catastrophic, Sept. 11-type event is inevitable. His conclusion: similar to Sept. 11's aftermath, when Bush created the Department of Homeland Security, we will create a new department, the Department of Cyber. Secondly, we will have a new version of the Internet. It will be slower and perhaps a bit clunky, but overall it will be safer and more secure.

Some may argue that these are simply doomsday scenarios. But for many, including our leaders in Washington, the threat is real. All it takes is a motivated hacker on one end, and a compromised network on the other. With attempted cyberattacks in the tens of million each day, one is bound to be successful – when it happens, the effects will be devastating.

Mark Vargas (@MarkAVargas) is a contributor to the Washington Examiner's Beltway Confidential blog. He is co-founder and president of tech startup Licentiam. From 2007-2010, he served as a civilian within the Office of the Secretary of Defense. From 2008-2010 he traveled to Iraq fourteen times.

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