Many of the most tragic days in American history feature a common thread: a surprise attack for which the United States simply was not ready. This is true of the sinking of the USS Maine that began the Spanish-American War. So too of Pearl Harbor, and the terrorist attacks of Sept. 11, 2001.

Each was a watershed moment that changed America’s approach to national security and the defense of our homeland. The lesson learned was that reacting was wholly inadequate when faced with rogue enemies and determined foes. Our Armed Forces would need to be on the front foot, anticipating and preparing for the next assault on our way of life.

It is with these painful reminders in hand that our military leaders must prepare to combat the ambitions of rogue nations such as North Korea and Iran. This concern is underscored by several complicating factors, including the recent disclosure that North Korea has reached out to Iran to trade weapons for oil; disclosure of a U.S. military intelligence report that North Korea could arm a ballistic missile with a nuclear warhead; and reports that Iran may be getting close to completing its effort to build a nuclear weapon.

The good news is that Americans can be sure that this rising tide of threats is being taken seriously at the highest levels of the U.S. government and military.

In the Pacific, the United States has positioned its Sea-Based X-Band Radar. The system, which resembles a giant golf ball atop a floating platform, is designed to track ballistic missiles and feed data to a separate command that can fire interceptors. Additionally, two anti-missile destroyers, the USS John McCainJohn Sidney McCainMulvaney aims to cement CFPB legacy by ensuring successor's confirmation Trump mocks McCain at Nevada rally Don’t disrespect McCain by torpedoing his clean National Defense Authorization Act MORE and the USS Decatur, have reportedly been sent to the region.

In recent weeks, Defense Secretary Chuck HagelCharles (Chuck) Timothy HagelOvernight Defense: Latest on historic Korea summit | Trump says 'many people' interested in VA job | Pompeo thinks Trump likely to leave Iran deal Should Mike Pompeo be confirmed? Intel chief: Federal debt poses 'dire threat' to national security MORE also realigned the United States’s missile defense funding priorities. The course change included adding 14 ground-based interceptors in Alaska and California, a rejection of President Obama’s previous plan to cut the number of interceptors from 44 to 30.

Last week, the Pentagon announced it has revamped and redesigned its “bunker buster” bomb to reach Iran’s deep caverns and to evade its sophisticated electronic defenses.

But additional measures should be considered. In the last year, North Korea has conducted three nuclear tests, displayed what appears to be a road-mobile intercontinental ballistic missile, and used its Taepo Dong-2 missile to put a satellite in orbit, thereby crystallizing its progress toward a long-range missile that could hit America. Coupled with its capability to launch hundreds of short- and medium-range ballistic missiles on our U.S. forces in Korea and our South Korean partners, we absolutely must provide our commanders in the field with whatever assets are available to mitigate or eliminate these threats.

The Army has had the lead to develop a program known as the Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System, or JLENS. JLENS utilizes surveillance and fire-control radar, seeing enemy aircraft and missiles from more than 340 miles away. In a highly publicized test in December, JLENS impressed defense experts when it successfully demonstrated an ability to track surrogate tactical ballistic missiles during their ascent phase.

Importantly, the system’s long-range, over-the-horizon detection capability provides combatant commanders additional minutes – not seconds – to react to incoming threats. Those extra minutes to identify a target and react could be the difference between war and deterrence, life or death.

Frank Kendall, under secretary of Defense for Acquisition, Technology and Logistics, wrote that this program is “essential to the national security ... there are no alternatives to the program that will provide acceptable capability to meet the joint military requirement at less cost.”

Despite the ringing endorsement, two JLENS systems sit idle in New Mexico and Utah. While one is slated to be demonstrated in the Washington, D.C., area next year, the Department of Defense has no plans for the second system. Rather than collecting dust here in the United States, it would seem reasonable to deploy these proven systems at this time, providing commanders with greater time to react to threats.

Our leaders in Washington would be well-served heed the famous words of Gen. George Patton: “A good plan violently executed now is better than a perfect plan executed next week.” Given North Korea’s growing belligerence, the United States must act now.

Anderson is a former head of the Army Space and Missile Defense Command.