WASHINGTON — Sunday, June 25, 1950, the Korean People’s Army attacked across the 38th parallel, captured Seoul — capital of the Republic of Korea — and began driving south. The battered South Korean army and their U.S. military advisers quickly were pushed into the “Pusan Perimeter” on the southern tip of the peninsula — and U.S. President Harry Truman took the case to the United Nations Security Council.

American leadership and the absence of the Soviet ambassador resulted in swift passage of Security Council Resolution 84. The measure — perhaps the last time in history that the U.N. acted with dispatch — authorized the use of force against the Democratic People’s Republic of Korea. During the bloody three-year war that followed, troops from 10 European countries and from 10 others around the world fought beside U.S. soldiers, sailors, airmen and Marines in Korea — finally securing an armistice July 27, 1953.

In the years since, the increasingly isolated patriarchal-Stalinist regime in Pyongyang, North Korea, has raised visceral hatred of the United States to a whole new level while systematically violating the terms of the armistice — and virtually every other agreement to which it is a party. In short, Pyongyang’s past behavior is a prelude to present and future conduct.

On Jan. 21, 1968, North Korean guerrillas attacked Seoul’s Presidential Palace in an attempt to assassinate South Korean President Park Chung-hee. U.S. President Lyndon Johnson dispatched Cyrus Vance to discourage the South Koreans — with troops already committed in Vietnam — from undertaking a military response. Vance’s mission was a success, and no action — other than a strongly worded diplomatic note — was taken against Pyongyang.

Two days later, the USS Pueblo, a small, unarmed U.S. Navy surveillance vessel, was seized in international waters by North Korean patrol boats. Cmdr. Lloyd “Pete” Bucher and the 81 surviving members of the Pueblo crew were beaten and tortured by their captors while the Johnson administration in Washington, enmeshed in micromanaging the war in Vietnam, dithered. Finally, after a year of brutality — and facing the threat of having one member of his crew shot each day, starting with the youngest — Bucher signed a concocted confession. Pyongyang promptly repatriated the crew, kept the Pueblo and still uses it for propaganda.

The unwillingness to deal forcefully with the North Korean regime in 1968 set a precedent from which neither the West in general nor the U.S. in particular ever has recovered. North Korean leaders, emboldened by the West’s flaccid response, stepped up their campaign of terror.

Intelligence operatives and commandos dispatched by Pyongyang have kidnapped hundreds of South Korean and Japanese mariners, fishermen and civilian women and children. North Korean terrorists have made no fewer than three additional attempts to assassinate South Korean leaders. One of them, a 1983 bombing in Rangoon, killed 17 diplomats and members of South Korean President Chun Doo-hwan’s security detail. In 1987, a bomb placed aboard Korean Airlines Flight 858 killed all 115 aboard — including four Americans.

In 1994, after North Korea’s “great leader,” Kim Il Sung, died of a heart attack at age 82, the Clinton administration opened direct negotiations with his son and successor, Kim Jong Il, and claimed it had forged a “new relationship” with Pyongyang. Since then, the Clinton, Bush and Obama administrations have delivered tens of millions of dollars’ worth of food, fuel and humanitarian aid to ease starvation. Despite this generosity — and toothless U.N. sanctions — little has changed except that North Korea has acquired nuclear weapons and the means of delivering them.

Last year, the despotic dynasty passed to the founder’s 27-year-old grandson, Kim Jong Un. Eager to prove himself to “old guard” Communist Party hacks and the military leaders actually running the hermit kingdom, Kim has upped the ante. In December, the Korean People’s Army launched a multistage missile capable of hitting the U.S. homeland. In February, North Korea successfully tested a nuclear weapon — and followed up with threats of a nuclear strike on the United States, Japan and South Korea. This week, North Korea moved a Musudan midrange mobile missile to a coastal test range on the Sea of Japan.

Official Washington’s response to this new round of North Korean saber rattling has exacerbated anxiety in Seoul, Tokyo and U.S. Pacific Command headquarters in Hawaii. Last week, the Obama administration launched a rhetorical counterattack against Pyongyang and widely publicized the deployment of strike aircraft, U.S. Navy surface combatants and ballistic missile defense assets — including two sea-based radar platforms and ground-based missile interceptors to Guam.

One senior military officer put it this way: “All this should have been done very quietly and reassured our allies. Instead, the Obama administration is turning this into their version of John Kennedy’s ‘Seven Days in May.’ If they keep this up, everyone out here will have nukes.”

Well put. The folks who canceled White House tours to save money need to get out their history books. The first occupant of the White House to receive a Nobel Prize was famous for saying, “Speak softly, and carry a big stick.”