President Barack Obama has completed his great reassurance tour of Asia. America's allies need not fear. No matter how wealthy, influential, or powerful, they can count on Washington's continuing protection.
So it is with South Korea. Behind America's shield, the South prospered, developing an economy now around 40 times the size of North Korea's.
South Korea also has twice the population, an overwhelming technological advantage, access to global markets and numerous important international friends.
Yet when President Obama arrived in Seoul, he announced: "The commitment that the United States of America has made to the security of the Republic of Korea only grows stronger."
The US is rather busy in the world. Why must Washington promise even greater support for a country well able to defend itself?
In one sense, South Korea's dramatic growth demonstrates the success of American policy. For years, without US backing, the South could have been overwhelmed by Pyongyang in a second Korean War.
But the correlation of forces began to change in the 1960s. By the new millennium the Korean race was over. Seoul had won decisively.
Only in terms of military power did Pyongyang remain ahead, and even there its advantage waned.
North Korea held that advantage only because the South chose not to invest more of its growing wealth in its military. This was something Seoul could do only because America was still protecting the South.
It is impossible to blame South Korea for taking advantage of Washington's misplaced generosity.
The US had no similar excuse for maintaining the status quo.
If there was no cost involved in defending much of the known world, there would be no problem with this policy. However, while everyone assumes America's promise to intervene will deter war, human history is littered with cases where deterrence failed.
Thus, the more Washington wants to do in the world, the more of Americans' money Washington must spend.
Moreover, giving out security guarantees from a major power usually makes recipients more confrontational, even reckless: after all, with a big brother willing to do the fighting, why not take advantage of the opportunity?
Finally, Washington's treaty commitments and force deployments discourage allied nations from doing more on their own behalf.
The worst danger for America arising from its commitment to South Korea is involvement in an unnecessary war, including with one or more nuclear powers in the region. After years of attempting to dissuade Pyongyang from building nuclear weapons, the US government appears to have concluded that North Korea is unpersuadable.
This realisation has left Washington officials searching for new approaches. In fact, news reports indicate that the problem posed by Pyongyang was high on the US President's agenda for his Asian trip. But the only reason the US needs be so concerned is America's military commitment to the South.
In the absence of Washington's promise to go to war on Seoul's behalf, North Korea would have little interest in America. Moreover, Pyongyang has an ability to harm the US only because Washington has generously stationed 28,000 men and women, plus additional dependants, within range of its artillery and tanks as well as missiles.
Of course, Washington promotes a general policy of non-proliferation. But that does not justify permanent defence treaties and garrisons.
Worse, it is not clear that nonproliferation works any longer in North-east Asia. Russia, China, and North Korea possess the doomsday weapon. America's democratic allies, Japan, South Korea and Taiwan, have no similar deterrent. Instead, they rely upon the US.
The risks associated with this policy increase as Beijing grows more aggressive.
It might be time for Washington to indicate that if Pyongyang continues to follow its present course, and China allows the North to do so, the US government would withdraw its objection to its democratic allies following the same path.
Dissolving the military alliance would not mean ending other forms of cooperation. Even security cooperation would be possible, indeed, desirable, without America promising to defend its wealthy friend.
The US-South Korea military alliance once made sense. No longer.
American policy will not have really succeeded until South Korea ends its embarrassing security dependence on Washington.
The writer is a senior fellow at the Cato Institute and former special assistant to former US president Ronald Reagan. He is the author of Tripwire: Korea And US Foreign Policy In A Changed World
This article was published on May 9 in The Straits Times.
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