The United States responded to a series of recent threats from North Korea Thursday by sending two B-2 stealth bombers to the Korean peninsula in a training exercise. The planes can be equipped with nuclear-armed missiles.

The Post’s Ernesto Londoño explains:

The sorties by B-2 bombers marked a rare show of force by the Pentagon on the Korean Peninsula and followed a decision this month to bolster nuclear defenses along the U.S. West Coast by adding 14 missile interceptors in Alaska.

“We have to take seriously every provocative, bellicose word and action,” [Defense Secretary Chuck] Hagel told reporters during a news conference at the Pentagon on Thursday afternoon.

North Korea has used heated rhetoric for years, but its recent statements and actions have “ratcheted up the danger,” Hagel said, adding: “We have to understand that new reality.”

Heightened tensions with North Korea began when the state conducted a nuclear test last month. The United Nations responded with additional sanctions, which, along with routine military exercises carried out jointly by the United States and South Korea, resulted in North Korea’s recent behavior.

Last week, a mysterious cyberattack shut down South Korean banks and television broadcasters. WorldViews blogger Max Fisher writes that the attack could have come from the North and describes a reported state hacking program there:

The government hackers... are sent to China or Russia for training and are rewarded with special housing and privileges for them and their families. They get such special treatment in part to reduce the temptation of defecting, given that the hackers are allowed rare access to the Internet and thus knowledge of the outside world’s relative prosperity.

On Tuesday, the North Korean army said that its artillery units had been placed on high alert and were prepared to strike targets in the United States. Pyongyang cut a military hotline with Seoul on Wednesday. Fisher, meanwhile, observes that North Korea’s military can’t carry out the state’s threats:

It is true that the North Korean military is very big, one of the world’s largest standing armies: 1.1 million troops! 4,200 tanks! 820 fighter jets!  . . .

Even the military’s size and political backing, though, can’t make up for North Korea’s isolation and impoverishment. Most of those fighter jets, for example, will never take off because the regime can’t afford enough fuel to fill them up. Even if they could somehow procure enough jet fuel, the fighters “would have been shot out of the sky in the first few hours of a conflict,” Dartmouth professor and North Korea-watcher Jennifer Lind told NPR recently. The tanks, likewise, are old and inferior.

According to the Associated Press, the recent provocations are a calculated bluff:

Despite the hastening drumbeat of warfare, none of the key players in the region wants or expects another Korean War — not even the North Koreans. . .

It’s all part of a plan to force Washington to the negotiating table, pressure the new president in Seoul to change policy on North Korea, and build unity at home — without triggering a full-blown war if all goes well.

Fisher agrees, pointing to a major North-South industrial facility that is still operating:

The Kaesong Industrial Complex, located just across the northern side of the border, is staffed by South and North Koreans. It can’t function without Pyongyang’s daily okay. If the North suddenly shuts down Kaesong at some point, watch out. But as long as it’s still running, as it has been throughout the provocations and tensions of the last few weeks, we can probably –  probably — assume that North Korea is not actually planning to launch a war.

Nonetheless, North Korean leader Kim Jong Un responded to the American B-2 training flights with undiminished belligerence:

Kim “convened an urgent operation meeting” of senior generals just after midnight, signed a rocket preparation plan and ordered his forces on standby to strike the U.S. mainland, South Korea, Guam and Hawaii, state media reported.

Kim said “the time has come to settle accounts with the U.S. imperialists in view of the prevailing situation.”

In Fisher’s analysis, Kim may not have been the intended audience for the U.S. military exercise. “It’s possible that the bombing test run was also meant as a message to South Korea,” he writes. “That would be a deterrence of a very different sort: not from war, but from the possibility that this long-reliant American ally might seek to develop its own nuclear weapons program.”