There is a reason why presidents of the United States of both parties have for years treated North Korea with restraint. We hope President Donald Trump, who appears to have some capacity to learn what he does not know, will come to understand the reasons for that approach.

Signs were not auspicious last week, as the Trump White House and North Korean President Kim Jong Un traded threats in advance of North Korea's celebration of the birth of its founder and Kim's grandfather, Kim Il Sung, on Saturday. The Hermit Kingdom had been expected to test a nuclear warhead during the festivities. Trump said the U.S. was sending "an armada, very powerful" — the aircraft carrier U.S.S. Carl Vinson and four warships — to the Sea of Japan.

North Korea did not test a weapon on Saturday, and a missile launched on Sunday promptly blew up for unknown reasons. By Tuesday, it had become clear the Carl Vinson Strike Group had actually sailed away from Korea, not toward it, and was thousands of miles away engaged in exercises with Australian forces in the Indian Ocean.

The strike group is now heading toward the Korean Peninsula, but isn't expected to reach the Sea of Japan until sometime next week.

Meanwhile, the rhetoric continued.

Vice President Mike Pence, visiting South Korea, announced on Monday that the "era of strategic patience is over," warned "all options are on the table," and said of Trump that "North Korea would do well not to test his resolve — or the strength of the armed forces of the United States in this region."

North Korea's deputy representative to the United Nations, Kim In Ryong, accused Washington of creating “a situation where nuclear war could break out at any time.” The regime has vowed to continue to test nuclear weapons in defiance of U.N. sanctions, and U.S. officials reportedly are concerned that the country is working on a missile that could reach the United States.

Meanwhile, however, the biggest threat North Korea poses is not to this country but to South Korea, which would be devastated by barrages from North Korean artillery trained on Seoul. Any preemptive strike by the U.S. would surely trigger massive retaliation by the North against the South.

For now, U.S. officials say the focus is on international sanctions, which they hope will include the assistance of China, to pressure North Korea to abandon its nuclear ambitions.

The last thing anyone wants to see is an all-out war on the Korean Peninsula. Let us hope Trump and his advisers recall that while "strategic patience" may not have ended the North Korean nuclear threat, it didn't provoke a shooting war, either.