The destroyer USS John Finn fired an interceptor missile Monday night and destroyed a threat-representative intercontinental ballistic missile in the broad ocean area northeast of Hawaii in a first-of-its-kind test that has tremendous ramifications for the future defense of Hawaii.

In fact, Congress mandated the test to be a “defense of Hawaii scenario” with Hawaii currently underdefended against North Korean threats, according to some missile defense experts.

At approximately 7:50 p.m. Monday, the target was launched from the Ronald Reagan Ballistic Missile Defense Test Site on Kwajalein Atoll toward the broad ocean area northeast of Hawaii, the Missile Defense Agency said.

In the “developmental test,” the destroyer used engage-on-remote capabilities as part of a defense of Hawaii scenario and fired an SM-3 Block IIA missile that destroyed the mock ICBM, the agency said.

It was the first test of the newer SM-3 Block IIA missile against an ICBM target, and the success will impact how other countries, including North Korea, China and Russia, view U.S. defensive capabilities.

“This was an incredible accomplishment and critical milestone” for the mainly ship-based SM-3 Block IIA program, Missile Defense Agency Director Vice Admiral Jon Hill said in a news release.

The Defense Department is investigating the possibility of augmenting the ground-based midcourse defense system by fielding additional sensors and weapon systems “to hedge against unexpected developments in the missile threat,” Hill said.

“We have demonstrated that an Aegis BMD-equipped vessel equipped with the SM-3 Block IIA missile can defeat an ICBM-class target, which is a step in the process of determining its feasibility as part of an architecture for layered defense of the homeland,” Hill added.

The intercept event, designated Flight Test Aegis Weapon System-44, FTM-44, was originally scheduled for May but was delayed due to restrictions in personnel and equipment movement due to the spread of COVID-19.

FTM-44 satisfies a Congressional mandate to evaluate the feasibility of the SM-3 Block IIA missile’s capability to defeat an ICBM threat before the end of 2020. The SM-3 Block IIA was originally designed and built for the Intermediate-range Ballistic Missile threat set.

The successful test moves what’s known as an “underlay” defense one step closer to reality for the Aloha State.

Hawaii has limited protection from 44 big ground-based interceptors mainly in Alaska but also California that protects the United States — and have to travel very long distances to intercept a North Korean missile headed for Hawaii.

The smaller SM-3 IIAs would be one more line of defense in Hawaii’s backyard.

Although a lot of focus now is on China, the Center for Strategic and International Studies noted that “North Korea’s ballistic missile program is a rapidly-developing threat to global security.”

The worries that prompted a mistaken Jan. 13, 2018, alert warning of a ballistic missile inbound to Hawaii haven’t gone away.

Adm. Phil Davidson, head of U.S. Indo-Pacific Command on Oahu, told the Missile Defense Advocacy Alliance in September that “North Korea, as long as they retain the capability to shoot long-range missiles and to continue to develop nuclear weapons, will remain, really, in my view, our most immediate threat.”

China, meanwhile, is the most significant strategic threat for the United States in the 21st century, he said.

The 2018 National Defense Authorization Act required for the “defense of Hawaii” a test no later than Dec. 31 of an SM-3 Block IIA missile to defeat a simple — meaning no counter-measures — ICBM-representative threat.

“The congressional language says to do a defense-of-Hawaii scenario. Do it with a ship and do the feasibility of the SM-3 Block IIA. The test is constructed right now to exactly do that,” Hill said in August during a Heritage Foundation interview.

The United States has a range of missile defenses: Patriot, Terminal High Altitude Area Defense, and Aegis ship-based systems that can defeat North Korean short- to intermediate-range ballistic missiles.

The 54-1/2-foot ground-based interceptors have a range of 3,728 miles compared with 994 miles for the 22-foot SM-3 IIA and 124 miles for 20-foot THAAD missiles, according to the Missile Defense Agency.

Hill said the SM-3 IIA will be stressed “outside its design space. It was designed for medium and intermediate-range (threats),” he said. “Now we’re going against a long-range intercontinental ballistic missile. The analysis says we’ll be successful, but nothing is real to any of us until we actually get the credible data from being out at the flight range.”

In February the agency said six SM-3 IIA missiles were being sought in fiscal 2021.

The missiles are being secured as the Defense Department pursues regional missile systems to provide a layered homeland defense.

Hill said Patriot can be thought of as an ability to defend a city, THAAD to defend a state and Aegis with the SM-3 able to defend a region, while the big ground-based missiles defend the country.

“You can imagine those as bubbles of protection or a shield across the country,” Hill said. “To me, it’s a no-brainer to have that sort of defensive depth.”

If the upcoming SM-3 IIA test went well, Hill said at the time “that allows us to now start to think through that architecture and start working more closely with war-fighters to determine where they would position the ship” for the defense of locations such as Hawaii, the mainland or Guam.

Another route to additionally protect Hawaii is using the Aegis Ashore Missile Defense Test Center on Kauai — which has fired an SM-3 IIA missile before.

The Pentagon previously said it would evaluate operationalizing the Pacific Missile Range Facility site to see whether it was a viable near-term option. The Missile Defense Agency reported in February the test site could be temporarily activated in the event of a national emergency for missile defense.