It would be hard to imagine President Obama ever standing only a few feet from the North Korean border and warning its leaders that if they ever used nuclear weapons, "it would be the end of their country."
Mr. Obama is not the threatening kind. He prefers "soft" power to win over his adversaries. In fact, after North Korea's May 25 test of a bomb close in size to the one dropped on Hiroshima, he said the US would merely "work with our friends and allies to stand up to this behavior."
What a contrast to the last Democratic president.
Mr. Clinton knew something back then that Obama is learning on the job: Tough talk against an enemy is sometimes needed simply to reassure America's allies that the US will live up to its defense promises. Those commitments include its unique role to provide nuclear deterrence, or promised retaliation, if an ally is attacked.
It's an impression he needs to correct quickly with credible reassurance.
Beyond Obama's lackluster response so far to North Korea's first successful atomic blast, Japan and South Korea worry that the president's focus on his big domestic agenda will erode the US military posture in Asia and the will of Americans to defend allies.
They worry that his proposed cuts in ballistic-missile defense would leave Asian allies vulnerable while his cuts in F-22 fighter jets would harm Japan's ability to build a similar plane to defend itself against China.
They watch as Obama cuts the US Navy's plans to build more ships to counter China's growing submarine fleet.
They worry about US willingness to defend Taiwan – as Bill Clinton did in 1996 – against a hostile confrontation with China. That worry stems from Beijing's recent success in luring Taipei's leaders toward closer ties with the mainland, thus weakening US support for Taiwan's sovereignty and its military strength.
Tokyo also notices that Obama has appointed a Democratic Party fund-raiser as US ambassador to Japan and not a professional diplomat with Japanese experience. And both Seoul and Tokyo are worried about signals that Obama will hold direct talks with North Korea without including them.
All these moves help explain recent steps in Japan and South Korea to prepare for an Obama era of American retrenchment.
Many legislators in Seoul now want to delay the planned 2012 hand-over of the wartime operational control of South Korean troops from the US. With North Korea soon able to place a nuclear weapon on a missile, they prefer the US keep its hand on a military response. South Korea also decided this week to join the US-led global effort to interrupt air or sea deliveries by North Korea of unconventional weapons or missile parts.
In Japan, officials are so worried about the reliability of the US nuclear umbrella that the ruling Liberal Democratic Party is debating whether to develop a capability to strike North Korea – "in order not to sit and wait for death," as an LDP committee stated this week.
Some LDP officials even want Japan to openly consider acquiring its own nuclear-weapons capability. They cite polls showing a drop in trust of the US by the Japanese public, caused in part by its weak stance toward North Korea.
Coincidentally, a US Council on Foreign Relations report released Tuesday warned Obama that if he doesn't reaffirm the US nuclear deterrence, "some US allies may decide in the future to acquire nuclear weapons."
Obama must not let North Korea's nuclear weapons ignite an arms race in Asia. The world must not again witness the kind of military rivalry between Japan and China that led to World War II.
In both words and deeds, the president must reaffirm a strong, long-term US military commitment to its many allies in the region.