Editorial Board The. The New Nuclear Proliferation Age. North Korea’s test shows the continuing failure of arms control. WSJ. 06 Jan 2015.

The temptation in most world capitals will be to denounce North Korea’s Wednesday nuclear test but do little beyond attempting to bribe dictator Kim Jong Un with more cash in return for more disarmament promises. The more realistic view is to see this as another giant step toward a dangerous new era of nuclear proliferation that the world ignores at its peril.

Pyongyang says the explosion, its fourth so far and first since 2013, was a “completely successful” test of a miniaturized hydrogen bomb. That would represent a technological leap, as H-bombs can be thousands of times stronger than the atomic weapons that North Korea tested previously. Pyongyang often lies, and the White House said Wednesday the initial U.S. analysis suggests it wasn’t an H-bomb.

But even an upgraded atomic bomb using boosted fission would give Kim a more powerful weapon than the bombs dropped on Hiroshima and Nagasaki. Kim is estimated to have enough uranium and plutonium production for 50 to 100 bombs by 2020.

This threat is growing well beyond Asia as the North makes progress on warhead miniaturization and missile delivery. U.S. Admiral Bill Gortney of the North American Aerospace Defense Command said last year that Pyongyang has “the capability to reach the [U.S.] homeland with a nuclear weapon from a rocket.”

The North conducted an apparently successful submarine missile test last month. Pyongyang helped Syria build a secret plutonium reactor that the Israeli air force destroyed in 2007, and it has worked with Iran on long-range missiles and possibly nuclear technology.

The larger story here is the rapid fraying of the world’s antinuclear proliferation regime, assisted by the illusion of arms control. The failure with North Korea goes back to Bill Clinton’s 1994 Agreed Framework, which he hailed as “a good deal” because “North Korea will freeze and then dismantle its nuclear program” in return for food and energy aid. The North took the cash and kept working toward a plutonium and uranium bomb.

The Bush Administration tried a tougher approach at first but lost its nerve in the second term and also went the bribery route. We’ve praised President Obama for not doing the same, but the Administration mustered no response to the North’s 2013 nuclear test and only light sanctions after its 2014 cyberattack against Sony. The North has now escalated.

The West wants to believe the Iran nuclear deal is an antiproliferation triumph, but Iran’s neighbors view it as a delaying action at best. They think it guarantees that Iran will eventually build a weapon. Over time this will encourage others in the Middle East to seek their own nuclear deterrent.

In Asia, too, the question is whether North Korea’s growing nuclear arsenal will now cause Japan and South Korea to get their own deterrent. South Korean President Park Geun-hye warned in 2014 that after a fourth North Korean test “it would be difficult to prevent a nuclear domino from occurring in this area.”

North Korea’s latest test should spur a new global resolve against Pyongyang, but it probably won’t. China once again expressed its disapproval but it has never been willing to squeeze its client state.

The U.S. could revive the targeted economic sanctions that in 2005 hit Macau’s Banco Delta Asia and forced others to cut ties with Pyongyang, squeezing its supplies of arms and luxury goods. The U.S. also hasn’t designated the North as a “primary money-laundering concern” despite its racket in counterfeit currency and drugs. The North Korea Sanctions Enforcement Act, long stalled in Congress, would fix such oversights.

At the very least the U.S. and South Korea could finally deploy the missile-defense system known as Thaad, for Terminal High-Altitude Area Defense. Beijing has pressured Seoul not to use the U.S.-built platform, which would integrate with U.S. and Japanese defenses. But Thaad is the strongest system available, and China’s patronage of Pyongyang is a main reason the region is under threat.

The only real solution is to put regime change at the heart of U.S. policy. This would mean stronger defenses in the South, stepped-up sanctions and enforcement to undercut Pyongyang’s illicit trade and access to foreign goods, as well as expanded efforts to facilitate the flow of refugees out of the North.

The Obama Administration has shown no inclination to do any of this, and it is unlikely to start now. The result is that while Mr. Obama entered office promising to pursue “a world without nuclear weapons,” he will leave having set loose a new era of nuclear proliferation.