People are in an uproar over President Obama’s speech last week at the United Nations. “The United States of America is prepared,” he said, “to use all elements of our power, including military force, to secure our core interests in the region.”

Note the word “core.” On that list are confronting external aggression, ensuring the flow of energy, dismantling terrorist networks and not “tolerating” the use of weapons of mass destruction. Not included was the promotion of human rights and democracy, which has outraged some liberals and even some conservatives for supposedly abandoning American idealism.

There was no new call to arms. No new mission to embrace. It was a small-ball vision, all about what was “core” and what was not. It was a signal to Americans and the world that the days of “big ideas” in foreign policy are over.

There’s clearly a downside to President Obama’s minimalism. Despite all the rhetorical reassurances to the contrary, he is indeed leading America into a new period of retrenchment and retreat. He’s gutting the military. His zigzags over Egypt and Syria have left the world wondering about the steadiness of U.S. leadership. His paying lip service to American idealism raises eyebrows on both the left and the right. “Neoconservatives” worry that a myopic realism in foreign affairs is just an excuse for an American retreat.

But there’s something interesting going on here politically.

In focusing on “core” national security interests, Mr. Obama’s attempt at prioritizing U.S. foreign policy is not all that different from what some Republicans are saying. For example, in a speech at the Heritage Foundation a few weeks ago, Sen. Ted Cruz, Texas Republican, said the main focus of U.S. military policy should be strictly on national security. He was trying to explain why he didn’t support a strike on Syria, but it was clear he was trying to limit the circumstances under which force should be used.

What’s bringing these two together is not a common ideology but a belief that new constraints need to be placed on the circumstances for using U.S. military force. Mr. Obama and Mr. Cruz have vastly different views about American power and its purposes. But the one thing they seem to agree on is that we should be careful about the circumstances under which it is applied.

Some fear that this represents a libertarian-liberal convergence that could drift off into a new left-right isolationism. But this is not likely to happen. Conservatives want constraints on the use of force not because they think it is morally questionable, as many liberals do, but because they fear its profligate use will backfire and weaken America.

Nevertheless, despite the potential for misunderstandings, there is nothing wrong with prioritizing which “core” interests warrant using force to defend. Here a more productive convergence may be possible. Not everything rises to the level of sending in cruise missiles or putting “boots on the ground.” Sometimes other instruments of power — diplomacy, targeted aid or even sanctions — will suffice.

Power is a tricky business. Use it and fail, and it is gone. Don’t use it all, and it ceases to exist. We indeed need a middle way, but not between some theoretical opposites of idealism versus realism. Nor should there be only a false choice between using force and not using it. Rather, the debate should be about which core interests require military force to defend.

We may find that maintaining a balance of global power in our favor not only suits our national security but also advances the cause of world liberty. This is not a choice between our values and our security but actually recognition that our security serves those values. Our military power should be preserved largely for big causes and military deterrence, not police actions around the world.

The sooner we realize this, the faster we can get American leadership back on sound footing.

 - Kim R. Holmes, a former assistant secretary of state, is a distinguished fellow at the Heritage Foundation.