President Barack Obama is learning what several of his predecessors knew - that North Korea is a very difficult challenge. Down through the years, its leaders have not hesitated to use brinkmanship of a consistency shunned by virtually all others in the community of nations.
Some analysts believe the current round of bellicosity from Pyongyang is an attempt to test Obama. It also could be a calculated effort to intimidate him.
North Korea's military is planning to test a new missile, one that could have enough range to reach the United States. As has been the case many times in the past, Pyongyang is warning that any attempt to interfere will mean war.
Saber rattling is being taken to an extreme in this situation. During the weekend, Pyongyang shut down a military hotline with South Korea. Such action involving other nations would be very alarming - but it seems to be no more than a new tactic for the North Koreans.
Obama's special envoy on North Korea, Stephen Bosworth, already has referred to the missile test as an "extremely ill-advised move." Unfortunately, North Korean leaders have made many "ill-advised" moves, including their ongoing program to develop nuclear weapons.
For years they have broken promises, threatened their neighbor, South Korea, and vowed that anyone interfering with them would be responsible for igniting a war.
We do not know how Obama can convince the North Koreans that he will not be cowed by their threats. But he should instruct his advisers to find some method, perhaps through economic sanctions, to demonstrate that he and this country will not be intimidated.