It can be unsettling when a neighbor stops talking to you.

But when that neighbor is North Korea, and you’re South Korea, such a communication cessation is downright alarming.

Yes, there is precedent for North Korea’s abrupt unplugging of a military hotline with South Korea this week — though it last happened in 2009.

And certainly the Stalinist regime’s bellicose rhetoric is nothing new.

Thus, it’s tempting to dismiss Wednesday’s warning from Pyongyang “that the Korean Peninsula now has the conditions for a simmering nuclear war” as status-quo bluster from communist throwbacks stuck in a Cold War time warp.

But such a ho-hum reaction could be dangerously naive.

After all, last month North Korea conducted a test of a nuclear weapon considerably smaller than those it had detonated in previous years. Two months earlier, it conducted its most successful missile test yet.

Those technological advances aim to produce a warhead small enough to be carried by a missile accurate enough to target South Korea, Japan and even Alaska. North Korea also boasted this week that it is capable of hitting not just U.S. bases in Hawaii and Guam but the U.S. mainland.

Presumably, however, Kim Jong Un, “The Great Successor” who took over North Korea’s dynastic government after his father Kim Jong Il’s death in late 2011, got a timely wake-up call Thursday on the hazards of pushing America too far: Two B-2 Stealth Bombers were dispatched from Whiteman Air Force Base in Missouri to the Korean peninsula for what U.S. Forces Korea called a “long-duration, round-trip training mission.”

The bombers dropped munitions on a range on an island off South Korea’s western coast to demonstrate America’s ability to conduct, in the USFK’s stern words, “long-range, precision strikes quickly and at will.”

That participation in ongoing military exercises with South Korean forces dramatically re-confirmed America’s continued support our long-time ally.

So did new Secretary of Defense Chuck Hagel’s Thursday assertion of the Obama administration’s “unwavering commitment” to protect South Korea from the rising threat of North Korean aggression.

Ideally, such demonstrations of American resolve will deter North Korea’s leaders from pushing their luck too far.

They have squandered their nation’s limited resources on martial endeavors even as much of the populace literally starved. As a result of those warped priorities, Kim and his cronies have an arsenal of roughly 13,000 artillery systems, 4,000 tanks, 1,700 aircraft and 800 naval surface vessels, according to U.S. Army Gen. James Thurman, the American commander in Korea.

Add up to 10 nuclear weapons (by a consensus count of experts) and those seemingly comic scenes of Kim being entertained by dancers portraying Disney characters last year offer dwindling comic relief.

Clearly, the international community must keep trying to convince North Korea that its reckless ways are ultimately futile — and extremely risky.

China, due to its long financial support of North Korea’s failed government and its geographic proximity, remains the nation best positioned to press that case. The U.S. State Department must persist in pushing China in that direction.

Meanwhile, though, the U.S. Air Force has delivered a needed reminder to North Korea’s rulers of the consequences to come if they escalate their tough talk into war.