Concessions made by North Korea on its nuclear program are likely the result of the Obama administration's refusal to give in to Pyongyang's belligerent demands, according to a former top White House aide on Asia policy.

Jeffrey Bader was the National Security Council's senior director for Asian Affairs from 2009 to 2011. He told VOA that North Korea was the most urgent and potentially dangerous challenge facing U.S. foreign policy in the region during those years.

He acknowledged difficulty in dealing with North Korea, describing it as a “land of bad policy choices.” But he said Washington, which does not have diplomatic relations with Pyongyang, has made the most out of its “rather formal and somewhat stilted” contacts with its delegates to the United Nations.

“We do have channels of communications with the North Koreans. They are not ideal and they are not extensive, but we do talk to them. … But I think the real problem is their policies and the character of the regime, not the communications channels.”

Pyongyang agreed last month to suspend its uranium-enrichment program and its nuclear and missile testing. At the same time, Washington agreed to negotiate terms for resuming its shipment of emergency food aid to the impoverished communist country.

Bader is the author of a new book titled “Obama and China's Rise: An Insider's Account of America's Asia Strategy,” which was published by Brookings Press earlier this month.

The book details the Obama administration's recently announced “rebalancing” of U.S. priorities toward the Asia-Pacific region. Bader says Mr. Obama's policy for the region was largely formulated in his first White House campaign. He says the president tried to avoid pitfalls of rhetoric that have hurt former U.S. presidents.

“I think we had pretty good continuity between what he talked about during the campaign and what we did. One of our objectives was to avoid mistakes of past campaigns, when presidential candidates talked about sharp changes in direction of U.S. policy towards China, with specific proposals on how to do it.”

Bader says, once elected, U.S. presidents often find it difficult to implement the sharp changes in policy toward China they had promised during their presidential campaigns.

He says China's rising global influence and assertiveness makes it increasingly necessary for future U.S. presidents to maintain America's strength while preventing an increase in tensions between the two powers.