South Korea and the US are key players in the efforts to cope with nuclear and missile threats from North Korea, which for now come in two forms -- sanctions and military deterrence.

It seems that punishing the North for its latest nuclear and missile provocations is on the right track. The UN has already imposed the harshest-ever sanctions against the Pyongyang regime and its key members.

The international community led by the US is straining the North’s economic system by ostracizing its international finance. Chinese firms working with North Koreans were put in a virtual secondary boycott. Some of the North’s remaining sources of foreign exchange earnings, such as exports of coal and labor, face restrictions. More sanctions by South Korea, Japan and European countries are in the making. 

The other pillar of the efforts to rein in the rogue regime in Pyongyang -- more urgent than sanctions -- is strengthening military deterrence, as the North is now seen as being closer to acquiring the capability to a strike with a nuclear-tipped missile.     

Deterrence against North Korea should include the capability to make pre-emptive strikes at signs of an imminent provocation, an effective missile defense system and readiness for a massive retaliation.

The South Korea-US alliance is critical in securing such a strong deterrence against North Korea. In that regard, last week’s high-level talks between the two allies in Washington were important.      

The talks, which involved top diplomats and defense chiefs of the two countries, focused on North Korea. South Korean Defense Minister Han Min-koo and his US counterpart Ash Carter held separate talks, which centered on joint military steps to counter nuclear and missile threats from North Korea.

A key issue was pushing the deployment of US strategic military assets to South Korea permanently on a rotational basis. This means the US keeps at least one of its strategic assets, such as long-range stealth bombers, nuclear-powered submarines or aircraft carriers, on standby on or near the peninsula.

That would be a good option for the allies. Most of all, it would provide an effective “extended deterrence” by Washington without causing the allies the burden of bringing US tactical nuclear weapons, which were taken out of South Korea in the early 1990s.

Han made it clear that the issue was a key agenda in his talks with Carter. He said after the talks that he and the US defense secretary discussed “a lot of options,” including permanently deploying US strategic assets on a rotational basis. Carter also said that the two sides were talking about a number of measures to further enhance deterrence.

But a joint communique issued after the Han-Carter talks only said the two sides agreed to “consider” the rotational stationing of US strategic assets. This raised speculation that the US was reluctant to agree to the plan.

Some interpret that the US wanted to maintain “strategic ambiguity” or considered the possible sensitive reaction from China. People with a pessimistic view of the US commitment argue that the communique showed a gap between the allies.

The two sides need to dispel such a concern. One of the first steps should be the early launch of a joint body they agreed to form -- the Extended Deterrence Strategy and Consultation Group -- and work out details of the US extended deterrence. One of its objectives should of course be reaching a full agreement on the rotational stationing of US strategic assets. 

Carter said that any attack on America or its allies would not only be defeated, but any use of nuclear weapons will be met with an “overwhelming and effective response.” Such words alone -- unaccompanied by concrete actions -- would not be enough to send a clear message to the North that any serious provocation would result in its total destruction.