Russian President Vladimir Putin is a threat to Asia. Let me explain why.

 Russian President Vladimir Putin is a threat to Asia. Let me explain why. His invasion of Georgia in 2008 and now Ukraine are blatant acts of aggression. Placing troops in Crimea is a violation of the sovereignty of another nation and reflects a desire on the part of Putin to re-establish some sense of preeminence enjoyed by the Soviet Union before its breakup. Of course, the referendum in Crimea last weekend dresses up Russian actions in the language of self-determination, but this is a blatant violation of international rules and norms.

What is most frustrating is that there is little that the United States can do to counter these actions. Washington can condemn Russia. It can refuse to recognize the referendum in Crimea. The United States can push for sanctions. It can invite Ukrainian leaders to the White House and take pictures with them. But in the end, Russia gets what it wants, largely because it has a higher level of commitment to the issue, while the United States does not. The United States is not going to go to war with Russia over Crimea.

So why should this matter for Asia? After all, Crimea is a distant place of marginal interest to most Asians. However, if Putin is able to pull off a fait accompli against Crimea based on the perception of a lack of US resolve or commitment, then what is to stop others from thinking the same way? Why shouldn't Xi Jinping think the same way regarding the claim of another air defense identification zone (ADIZ)? Or why shouldn't Kim Jong-eun feel that a fait accompli action in the West Sea would work to his advantage?

Crimea shows that power matters less than commitment. And as powerful as the United States is, it is not as committed to Crimea as Russia. The danger of Putin's actions is the "demonstration effect" - it sets a bad precedent for others to follow.

How do we prevent others in Asia from acting like Putin? In Asia, the answer is to create a strategic environment that effectively deters China or North Korea from ever considering such actions. It requires instilling in these countries a belief that Crimea-type actions are so outrageous and would be met with such reprobation from everyone in the region that it would deter them from contemplating such acts.

The key to creating such an environment is the maintenance of regular US consultations with allies and partners. This is why the ongoing US-South Korea military exercises are so important. It is why closer US-Japan military cooperation, including the right of collective self-defense and revision of the defense guidelines is critical. It is also why US arms sales and high-level visits to Taiwan are necessary. These may seem like discrete acts when taken in the bilateral context between the United States and its partners, but taken together they help to define the strategic context that deters others from risky gambits.

But an equally important element is to improve Japan-South Korea bilateral relations and US-Japan-South Korea trilateral coordination. If North Korea sees a rift among the three countries, then they are not creating the right strategic environment to prevent Putin-like actions in Asia.

This is why it is so important now to take advantage of the opportunity to improve Japan-Korea relations. Prime Minister Shinzo Abe's said in the Diet last week that he will not revise war apology statements that admit culpability and apologize for Japan's forcible wartime conscription of sex slaves. This meets Seoul's primary complaint about his dodging of the comfort women issue. The Blue House expressed relief at Abe's decision. Now is the window of opportunity for Seoul and Tokyo to re-engage and focus on the strategic merits of cooperation going forward. This will provide a face-saving way for both leaders to engage on the sidelines of the nuclear summit at the end of this month at The Hague.

There is a full agenda for Japan-South Korea relations after the long period of non-dialogue. This list includes an FTA, currency swap arrangement, military information-sharing agreement, and military parts servicing agreement.

Reconciling Japan-South Korea relations is good for both countries in terms of their own security to prepare for the next North Korean provocation. In the longer term, it is important for setting the strategic environment that avoids a Crimea in Asia.

Victor Cha (chav@georgetown.edu) is a professor of government at Georgetown University and senior adviser at CSIS.