US worried that North Korea's leader could really start war

Obama administration officials who once hoped that North Korea's young leader could prove to be a reformer are increasingly worried that he might blunder his way into a war.

Even as they publicly describe 30-year-old Kim Jong Un's recent bellicose threats as bluster, administration officials have stepped up visible demonstrations of American military power.

The aim, according to current and former U.S. officials, is to highlight for the North Koreans that their Stalinist regime might not survive a war on the Korean peninsula.

Kim "is clearly inexperienced, but what's not clear is whether he has the smarts to know ' or can learn ' that it wouldn't be wise to start a war," said a senior Defense official, speaking anonymously to discuss military planning.

The actions mark a change of tactics by the administration. During President Obama's first term, the White House played down North Korean threats and avoided visible reaction to provocations.

This time, it has staged a series of military moves, highlighting them with public announcements.

The Pentagon on Thursday took the unprecedented step of announcing that it had dispatched two nuclear-capable B-2 stealth bombers to fly a round-trip mission from their base in Missouri and drop dummy bombs in South Korea.

Also this month, the Pentagon sent nuclear-capable B-52 bombers over the peninsula and announced that it had bolstered missile defense forces in Alaska with 14 interceptors in response to North Korea's threats of missile attacks.

Kim has continued to escalate his threats against the United States and South Korea, on Friday ordering his missile units to be prepared to strike both nations, according to the state-controlled news media.

The Korean Central News Agency released a photo of Kim and his generals, with a map in the background that appeared to show the flight path of missiles from North Korea to Los Angeles and other American destinations.

The new, more confrontational U.S. approach has risks, however. With Kim believed to be eager to prove his strength, the U.S. strategy could provoke the kind of miscalculation that officials say they are trying to avoid.

In recent statements, North Korea has threatened to "break the waists of the crazy enemies, totally cut their windpipes and thus clearly show them what a real war is like."

U.S. officials believe that North Korea is still years away from being able to strike the United States with a nuclear missile, except possibly parts of Alaska and remote territories.

They see the threats by Kim as partly designed to consolidate his control of the regime he inherited when his father died in 2011.

But that hardly eliminates the risk of war. North Korea remains capable of threatening South Korea with a massive conventional attack.

The South's capital, Seoul, with a population of nearly 11 million people, lies well within range of North Korean artillery.

American officials fear that the North's bellicose rhetoric, its severing of communication links and South Korea's vows to retaliate against North Korean moves could lead to miscalculation and even violent clashes, with the potential for a full-scale war.

Beyond warning the North, the administration wants to reassure South Korea and Japan that the United States is committed to their protection so they don't need to expand their own military capabilities.

Tension in the region is already high, in part because of disputes between Japan and China over islands that both claim.