On April 19, 1995, Timothy McVeigh detonated a truck bomb in front of the Alfred P. Murrah Federal Building in Oklahoma City. The attack killed 168 people, including 19 children and a large number of federal employees. McVeigh sought revenge against the federal government, which he held responsible for the lives lost during the Waco Siege that had occurred exactly two years prior. Now, twenty years after the Oklahoma City bombing, the threat of homegrown terrorism is still alive and well.

U.S. security and intelligence officials just foiled three terrorist plots in the course of three weeks. While this stands as a testament to how much intelligence capabilities have improved since 1995, the frequency of attempts also demonstrates the seriousness of the threat. The arrest of John T. Booker on April 10 marked the 66th Islamist terrorist plot against the U.S. homeland since 9/11, with at least 55 of those plots being homegrown. ISIS and al-Qaeda continue to motivate and facilitate homegrown terrorism, and global dependence on cyberspace provides a new arena in which malicious actors can target U.S. interests.

Although the security environment has dramatically changed since the 1995 attack, counterterrorism capabilities must be continually renewed and improved. The 1995 attack, considered the most deadly homegrown terrorist attack in U.S. history, together with 9/11 and other deadly terror attacks in the past two decades, prove that the costs of terrorism are too high to tolerate complacency.

In order to stay ahead of the evolving threat, the U.S. must continue to bolster its counterterrorism capabilities by implementing a variety of reforms, including streamlining U.S. fusions centers, refocusing the Department of Homeland Security’s intelligence capabilities, maintaining essential counterterrorism tools, and facilitating information sharing with state, local, and private-sector partners.

History teaches us the dangers of having a reactive approach to terrorism. The U.S. must embrace a proactive approach to prevent future Timothy McVeighs and 9/11 hijackers from attacking our homeland.

—Rachel Zissimos and Jennifer Guthrie are currently members of the Young Leaders Program at The Heritage Foundation. For more information on interning at Heritage, please click here.