A CHILD starving in South Sudan should matter to Americans.

That was the message delivered last week by Nancy Lindborg, whose job at the U.S. Agency for International Development (USAID) is to lead a federal bureau spreading democracy and humanitarian assistance across the world.

That world has reached a critical danger zone, with three high-level crises combining military conflict with humanitarian catastrophes affecting millions of innocents in Syria, the South Sudan and the Central African Republic.

But back to that child.

In the United States, there is a tea-party fueled isolationism sweeping the domestic political culture. It has caused many Republicans to seek massive cuts to the foreign-aid budget, which - after you strip out diplomacy and military aid to foreign governments - accounts for less than 1 percent of federal spending.

Last week, the House passed a budget authored by Budget Committee chairman Paul Ryan, R-Wis., that cuts the foreign aid budget by 11 percent. It would also cut spending on domestic programs, including food stamps, by $5.1 trillion over 10 years. Every Democrat and 12 Republicans voted against it. Fortunately it has no chance of being considered in the Senate.

Lindborg argues that an America that continues to be the leading provider of humanitarian aid across the world is a stronger America, and that there are economic and security repercussions if you have unchecked economic crises in the world.

Consider Syria, for example. The civil war there has created an economic and humanitarian catastrophe as 2.6 million Syrian refugees have overwhelmed neighboring countries. Refugee camps are prime recruiting grounds for extremists. The resentment could eventually wash back to America's shores in the form of terrorism fueled by massive and sustained poverty for all but the ruling class.

Former Ambassador Jerry Feierstein, a deputy assistant secretary for Near Eastern Affairs, says there is growing concern that radicalized American Muslims are, like extremists in other countries, flowing into Syria to receive training. Whether in Syria or Sudan, much of the unrest is fueled by economic concerns, rooted in massive income inequality that is fomenting anger all across the world.

The growing global nature of the economy makes it possible for the United States to use economic sanctions to try to affect Russia's growing aggression in Ukraine. But it also makes crises in Africa or Asia or Latin America more likely to have a direct effect on both economic and security concerns here.

Sadly, our nation seems more interested in tracking the daily effort to find a missing Malaysian airliner than in recognizing that political and climate disasters are creating a huge new class of poor, huddled masses yearning for help from the only country still big and strong enough to provide a blanket of hope.

The Daily News occasionally runs editorials from other sources. This first appeared in the St. Louis Post-Dispatch.