By Chris Stewart, New York Times

DAYTON, Ohio -- The amount of money federal and state governments have spent on homeland security measures to prevent another 9/11 is staggering.

More than $1 trillion has been spent on domestic counterterrorism efforts since al-Qaida hijackers turned passenger planes into guided missiles 15 years ago. Trillions more have gone toward other intelligence and military spending to wage the War on Terror overseas.

What's driving the spending upward is fear, not the facts, said John Mueller, a senior research scientist at Ohio State's Mershon Center for International Security Studies and a senior fellow at the libertarian Cato Institute in Washington, D.C.

The worst terrorist attack in U.S. history left Americans feeling vulnerable and a handful of others since keep citizens on edge. A full 40 percent of Americans believe they or a family member will fall prey to a terrorist. More than 80 percent say ISIS is a critical threat to the United States, according to 2015 Gallup polling.

The level of fear Americans feel -- often fueled by politicians and news reports -- isn't supported by the actual terrorism threat, which remains low, Mueller said.

But no one in authority at the time and few since contemplated whether the attacks on the World Trade Center and Pentagon that killed nearly 3,000 Americans were "an aberration rather than a harbinger" of future terrorist plots, writes Mueller and a co-author in "Chasing Ghosts," a book examining the effectiveness of counterterrorism efforts since 9/11.

An American has about a 1 in 4 million chance of being killed by a terrorist on U.S. soil, which has resulted on average seven deaths a year. One is far more likely to die from lightning or getting struck by a deer, Mueller said.

"No one wants to talk about acceptable risk. But clearly we do accept a lot of risk. We can't get risk down to zero in anything: automobiles, surgery, or a deer running across the road," Mueller said. "We basically live with those threats."

Spread among an array of civilian agencies, federal homeland security spending on programs to combat terrorism and protect critical infrastructure will reach $50.4 billion in 2017, an 11.5 percent increase over 2016, according to a Federal Times budget analysis.

The Department of Homeland Security will get the lion's share, almost $37 billion, allocated to preventing terrorism and identifying cybersecurity threats.

Part of that money is funneled to Ohio Homeland Security. But a bulk -- $2.15 million -- of its $2.61 million 2016 budget was funded by state taxpayers.

Critics like Mueller say a good chunk of the money put toward counterterrorism efforts enters a black hole under little oversight and ultimately produces few actionable results -- largely because there are nowhere near the number of terrorists at work the government claims.

Richard Zwayer, Ohio Homeland Security executive director, said the threat to America is not exaggerated. Rarely does a day go by without the Statewide Terrorism Analysis and Crime Center, Ohio's designated primary "fusion center," receiving a tip related to potential terrorist activity, he said.

"It's no surprise to people throughout the United States, when you look at incidents like San Bernardino and Orlando, that the threat of terrorism remains very real for Americans," Zwayer said. "We've had recent reminders that ultimately we are not 100 percent safe from these things happening."

"I can tell you the risk of not doing the work we do could certainly lead to another 9/11 in the future," he said. "If local law enforcement and state law enforcement, federal law enforcement were not sharing information, gleaning that information, and developing intelligence from it, could there be another day where we had another 9/11? Certainly.

To Learn More:

Sen. Coburn’s Parting Shot Blasts Failures of Homeland Security Dept. (by Noel Brinkerhoff, AllGov)

South Dakota has Raked in $100 Million in Homeland Security Grants Despite No Known Terrorist Threats…Ever (by Noel Brinkerhoff, AllGov)

U.S. Counter-Terrorism Apparatus is used to Quell Dissent among Americans (by Noel Brinkerhoff, AllGov)

Homeland Security Fusion Centers: Surveillance Gone Wild (by Matt Bewig, AllGov)