The disaster in Japan reminds us that in an epic catastrophe, a nation may be forced to deal with a wide range of troubles. Such disasters are often referred to as “black swans,” dangers we view as remote and thus don’t dwell on — but that prove incredibly difficult to handle if they do occur.

In Japan, officials wisely ordered people to “shelter in place” to avoid unnecessary radiological exposure. Unfortunately, truck drivers — fearing contamination — refused to deliver goods to towns near the nuclear reactors. Now the locals are running out of food.

When a government tells people to shelter, it should have a plan to get them supplies and medical aid. Without a workable plan, there’s a problem. Tokyo has a problem.

In the midst of a crisis, government must deliver a credible response. When people think government is functioning and responsible, they react with discipline, composure and self-confidence. When they think government has failed them, things start to break down. Tokyo has watched its credibility melt as fast as the core of the damaged nuclear reactors. That is a problem, too.

There’s an old combat saying: “You can’t have enough friends in the foxhole.” That holds true in any disaster, not just a shooting war. Successful response means using the resources at your disposal to maximum effect. In the U.S., one crucial capability for disaster response that is woefully underused is State Defense Forces.

The Founding Fathers believed that a well-regulated militia was “the ultimate guardian of liberty.” They codified that in the Constitution. Article 1, Section 8 of the U.S. Constitution reserves for the “States respectively, the Appointment of the Officers, and the Authority of training the Militia.” States have raised and maintained them ever since.

Today, the best-known “militias” are the National Guard units that serve under the command of state governors and the civil authorities in U.S. territories (including the District of Columbia). Those can be federalized and serve as part of the “active-duty” military.

In addition to guard units, 23 states and territories have defense forces. Unlike the National Guard, those forces serve no federal function. In times of both war and peace, State Defense Forces remain solely under the control of their governors or territorial officials and are available for rapid deployment in the event of a natural or man-made disaster. Arguably best of all in this era of tight budgets, the defense forces are all-volunteer units.

Those forces are an important resource for the states that have them. The Alaskan State Defense Force aids in safeguarding the Alaska oil pipeline. After Sept. 11, 2011, the New York Guard, New York Naval Militia and New Jersey Naval Militia were activated to assist in response measures, recovery efforts and critical infrastructure security.

State Defense Forces can cross state lines to serve their fellow Americans. Forces from at least eight states, including Texas, Maryland, Virginia and Tennessee, contributed more than 2,250 highly skilled volunteers in support of recovery efforts after Hurricane Katrina. Some traveled to Louisiana and Mississippi to provide direct assistance to victims. Others stayed in their states, taking over the responsibilities of National Guard units that were deployed to assist in the recovery.

These volunteer groups are particularly effective. Many are filled with retired military, law enforcement and emergency managers, providing a wealth of disaster-response experience. Technical units such as medical and communication squads are staffed by trauma surgeons, cybersecurity engineers and other career professionals.

In many cases, these volunteers have proved to be the best and most dependable responders. They dedicate their time and often pay for their own training and equipment. They are the most committed kind of volunteers — and the most cost-effective. In 2002 alone, for example, the Georgia State Guard reportedly saved Georgia $1.5 million by providing 1,797 days of operational service to the state.

In a large-scale catastrophe, these organized, disciplined and capable responders could serve a vital role. Yet 28 states and the District of Columbia have chosen not to create such forces.

In some of those jurisdictions, proposals to create Defense Forces have met resistance from the adjutant generals (who command state and territorial National Guard forces). Such objections make little sense, given that these forces are entirely volunteer organizations and offer the states a robust, low-cost force multiplier.

The District of Columbia has a bill under consideration to create a defense force for the city. Now — before disaster strikes — is the right time to think seriously about establishing guards.

James Jay Carafano is a senior national security analyst at the Heritage Foundation.