Despite the rising hostility, there has been a noticeable shift in North Korea's rhetoric to a message that seeks to balance efforts to turn around a moribund economy with nuclear development.
"There was a danger that this was getting to the point ... of a permanent war footing," Delury said. "In the midst of this tension and militant rhetoric and posturing, Kim Jong Un is saying, 'Look, we're still focused on the economy, but we're doing it with our nuclear deterrent intact.'"
On Sunday, Kim and top party officials adopted a declaration calling nuclear weapons "the nation's life" and an important component of its defense, an asset that wouldn't be traded even for "billions of dollars." Pyongyang cites the U.S. military presence in South Korea as a main reason behind its drive to build missiles and atomic weapons. The U.S. has stationed tens of thousands of troops in South Korea since the Korean War ended with a truce, not a peace treaty, in 1953.
While analysts call North Korea's threats largely brinkmanship, there is some fear that a localized skirmish might escalate. Seoul has vowed to respond harshly should North Korea provoke its military. Naval skirmishes in disputed Yellow Sea waters off the Korean coast have led to bloody battles several times over the years. Attacks blamed on Pyongyang in 2010 killed 50 South Koreans.
Under late leader Kim Jong Il, North Korea typically held a parliamentary meeting once a year. But Kim Jong Un held an unusual second session last September in a sign that he is trying to run the country differently from his father, who died in late 2011.
Parliament sessions, which usually are held to approve personnel changes and budget and fiscal plans, are scrutinized by the outside world for signs of key changes in policy and leadership.