The unleashing of nuclear-attack capable B-2 stealth bombers on the Korean peninsula last week and a series of other recent U.S. actions may have rattled North Korea and cause it to think twice before making any new military provocations.
But now that the message has been made clear, can the U.S. and its military ally South Korea use the diplomatic route to ease tensions with the unpredictable North Korea?
For the first time, the United States announced last week that two of its B-2 Spirit bombers flew to South Korea and struck virtual targets during joint war games and returned home in a single, continuous flight of over 6,500 miles (10,460 kilometers).
In an obvious show of force in the face of North Korea's expansion of its nuclear arsenal, the stealth bombers had joined an American nuclear attack submarine and B-52 atomic-capable bombers in the joint military drills.
The B-2 bomber exercise was to test U.S. capabilities to carry out a particular military mission and clearly signaled a U.S. commitment to support extended nuclear deterrence of its allies, South Korea and Japan, in the face of North Korea’s nuclear development, said Victor Cha, a former White House Asia expert.
"While the operation was an exercise, the North undeniably must have been unsettled by this demonstration of long-range force projection by the United States," said Cha, now a senior analyst at the Washington-based Center for Strategic and International Studies (CSIS).
The B-2 test flights followed other U.S. government actions taken over a couple of weeks.
North Korea has been ramping up its saber-rattling ever since the United States and South Korea started war exercises in early March and its bellicose language escalated when the United Nations tightened sanctions in response to the North's nuclear and missile tests.
Pyongyang also declared that the armistice that stopped the Korean War in 1953, as well as all nonaggression agreements with South Korea, have been nullified.
On Friday, North Korean leader Kim Jong Un appeared in front of a map titled "Plans to Attack the Mainland U.S." The map listed targeted states including California, Texas, Washington, and New York.
A day later, the North declared it was in a "state of war" with the South and warned Seoul and Washington that any provocation would swiftly escalate into an all-out nuclear conflict.
By Sunday, a meeting of the central committee of North Korea's ruling Workers' Party, chaired by Kim, decided that the country's possession of nuclear weapons "should be fixed by law," the official KCNA news agency reported without elaborating.
Is there a real danger of conflict on the Korean peninsula? If the U.S. has sent a clear signal to Pyongyang of the repercussions of any of its new military actions, what steps must now be taken to dial down the escalating tensions?
"[N]ow that this message has been delivered, there is a need for the United States and South Korea to offer some clear diplomatic gestures of reassurance toward the North that can help the North Koreans climb down, calm down, and change course,” said Scott Snyder, a Korea expert at the New York-based Council on Foreign Relations.
Experts also are worried that the young Kim, being in charge of a dangerously militarized state, may take erratic actions.
"His recent rhetoric and actions show that he is willing to test the boundaries of what is internationally acceptable," said Strobe Talbott, the president of Washington-based Brookings Institution, who lead an in-house discussion with experts at the weekend on the latest saber rattling by North Korea and exploring the intentions of Kim Jong Un.
"But, I had the impression that he was subject to a lot of supervision from the North Korean military, meaning he doesn't have much autonomy, especially, one hopes, when it comes to declaring the Korean War back on and taking other actions that would significantly escalate the situation," Talbott said.
'Same old' typical way
The consensus opinion among experts is that North Korea’s recent actions are the "same old" typical way it responds to U.S.-South Korea military exercises every year, said Richard Bush, a former senior State Department official.
"The intensity this time may have been dialed up a bit because Kim 3.0 is feistier than his father was, but it's a question of degree," he said, referring to Kim as the third leader in the Kim dynasty after his father Kim Jong Il and his grandfather Kim Il Sung.
Bush, now a Northeast Asia expert at Brookings, said the junior Kim may order a "limited conventional strike at the the demilitarized zone between North and South Korea or against a South Korean naval ship, or one of the West Sea Islands, such as Yeonpyeong Island, which came under attack in November 2010.
"The [South Koreans] have pledged retaliation, which does create the problem of escalation, but how it might play out is speculative at this point," he added.
Jonathan Pollack, an East Asian international politics and security expert at Brookings, said there needs to be a much more determined effort by the United States and South Korea to deal fully with China in the event that things go from bad to worse in Korea.
"Now is definitely the time, lest we find ourselves in an acute crisis," he said.
North Korea's main diplomatic ally and biggest trading partner and aid provider, China, appears to be increasingly irritated by Pyongyang's recent actions and recently supported tough U.N. Security Council sanctions on North Korea over its third nuclear test.
China had been brokering multilateral talks aimed at ending North Korea's nuclear weapons program but the North Koreans walked out of the talks in 2009.
While the Chinese blessed Kim Jong Un's succession about a year before his father's death, no senior Chinese official has met with him since then, and he has not been invited to visit China, Pollack noted.
"In contrast to the distinct warming in China-South Korea relations, [including several messages between President Xi Jinping and President Park Geun-hye], there is a decided coldness/distancing in China-North Korea relations," he said.