Early Tuesday, North Korea fired an intermediate range ballistic missile over Japan's northern Hokkaido Island. It broke up shortly afterward over the western Pacific Ocean.

With this provocation, North Korean tyrant Kim Jong Un has blunted American optimism that he might be willing to trim his saber rattling. It is clear that further U.S. action is required to force him into constructive diplomacy. The time has come for the Trump administration to take action.

An invasion of North Korea would entail an immense loss of life and is clearly not on the cards. But there are measures a long way short of such hostilities that could prove effective and which President Trump should now employ. He should issue a clear statement of policy that the U.S. military will from now on shoot down North Korean intermediate or intercontinental ballistic missiles if Kim launches them in a way that poses a threat to America and its allies.

Trump should first affirm that he will unilaterally shoot down missiles threatening U.S. territories. But he should also seek an agreement with Japanese Prime Minister Shinzo Abe toward joint action. If a bilateral agreement were to be reached, it would attract diplomatic support from the European Union and other powers. This establishes that ballistic missile aggression will not be tolerated.

How does one define a launch that is "threatening," a threshold that would justify downing a North Korean missile? The definition should apply to any launch that puts the missile on a course that would transit or strike a U.S. ally or come within 700 miles of an American territory such as Guam. This would exclude the destruction of short-range missiles or missiles on their launch pads, which could invite international suggestions that the U.S. was escalating conflict. At the same time, however, it would be sufficient to secure American interests and send an unmistakable message of resolve and demonstrate technical capabilities that should make Kim pause.

There is still further utility to this new approach beyond the defense of the U.S. and its allies. By eliminating North Korean ballistic missiles at their midcourse or terminal phases, the U.S. would deny North Korea the technical data it needs to perfect their missile program. North Korea's ballistic missile program remains in its late developmental stage, and its scientists need data from each test to eliminate weaknesses. By destroying Kim's missiles, the U.S. would reduce his data returns and impose expensive losses on his capital investment project.

This shoot-down policy would also help perfect our ballistic missile defense capabilities. Whether confronting North Korea or other states such as Iran, the U.S. needs to develop reliable missile defenses. As it navigates an era of escalating ballistic missile proliferation, America needs credible missile deterrence.

There is a diplomatic solution, but it will only succeed if China believes the alternative is U.S. military action against North Korea. That option remains as impractical as it is unacceptable. But if the U.S. doesn't act fast, it might become unavoidable.

REPRINTED FROM THE COLORADO SPRINGS GAZETTE