More than a week into military operations in Libya, President Obama finally went before the American people in a televised address, explaining what we are doing there and why we are doing it.

We have been justifiably puzzled. Why are we bombing this country? Libya has not attacked us and is presently no threat to us. True, Qaddafi was gunning down his own people in Tripoli and was poised to "cleanse" the rebellious city of Benghazi without mercy.

On the one hand, it seems heartless to do nothing while 700,000 people are mowed down like grass. At the same time, we are wary of taking on responsibility for policing the world. That's a busy beat.

In 1821, Secretary of State John Quincy Adams warned us against playing international Messiah, going about "in search of monsters to destroy." Cultivate liberty at home, he said, as a beacon for all nations, and wish those well who undertake to win their own liberty. But America, Adams added, "well knows that by once enlisting under other banners than her own, were they even the banners of foreign independence, she would involve herself beyond the power of extrication, in all the wars of interest and intrigue, of individual avarice, envy, and ambition, which assume the colors and usurp the standard of freedom."

But President Obama offered a defense of humanitarian military intervention in what may be called his non-doctrinaire Obama Doctrine:

"I will never hesitate to use our military swiftly, decisively, and unilaterally when necessary to defend our people, our homeland, our allies and our core interests. . . . There will be times, though, when . . . the course of history poses challenges that threaten our common humanity and our common security. . . . In such cases, we should not be afraid to act-but the burden of action should not be America's alone. As we have in Libya, our task is instead to mobilize the international community for collective action."

We must act with force when something threatens "our interests and our values," or more specifically "justice and human dignity."

Where do Christian principles point on this question? Isolation or intervention? At first glance, they seem to support Adams. While the Lord gave civil government the power of the sword, He also limited that power to particular purposes. Domestically, it's the power to punish crime, even with death. Internationally, it's the power of war. In both cases, it's the power to defend the governed. Thus, patrolling the globe in defense of people who live under other governments is at least questionable.

But the moral impulse to challenge governments that are no longer governments but now are wild beasts falling upon human prey is spiritually healthy. Isn't it the love of neighbor that compels us? Technology has so shrunk the world that genocide in Rwanda or Libya has become like the woman who cries out for help from a dark alley. You act!

Nations stand in relation to one another like individuals. The Bible often speaks of nations as separate moral entities with accountability before God as nations. If that is true, how far does this wealthy superpower's responsibility extend for our worldwide neighbor-nations?

Individually, your obligation to help others is not absolute. It depends in part on proximity and relationship. You have greater responsibility for your family than for your friends, for those who cross your path than for those across the globe. It is also limited by your capacity to respond. You are not obliged to commit so much time to the needy that you lose your job. In the age of global power and instant mass communication, all these principles apply to nations as well.

In light of this, consider what President Obama said. Recognizing our need to "measure our interests against the need for action," he made a limited argument for intervention in Libya. "In this particular country-Libya-at this particular moment, we were faced with the prospect of violence on a horrific scale," he said. "We had a unique ability to stop that violence." No universal declaration of war against monsters in this speech. A president must consider political, economic, and military feasibility.

Humanitarian military intervention is, at times, a moral obligation that all nations share and should shoulder: "The burden of action should not be America's alone." Rather, America, as de facto world leader, should "mobilize the international community for collective action." Obama did not cede that role to the UN, but nor did he free the world from moral responsibility for their neighbors' atrocities.