North Korea's recent underground nuclear test has renewed debate in Washington about how to deal with regimes seeking to become nuclear powers. Defense analysts say the Obama administration's reaction to Pyongyang's tests will be closely watched by Iran, which is believed to have nuclear ambitions.
North Korea's willingness to defy a United Nations ban on nuclear and missile tests is proving to be a critical trial of President Obama's foreign policy. His defense secretary, Robert Gates, recently issued a stern warning to Pyongyang at a security conference in Singapore.
"We will not stand idly by as North Korea builds capability to wreak destruction on any target in the region, or on us," he said.
The warning was in response to North Korea's announcement last month that it had tested its second nuclear device in three years.
Tom Scheber, of the National Institute for Public Policy, says the United States is now under pressure to prove it is not bluffing.
"Iran is watching to see how we respond to North Korea," he noted. "And similarly, anything that Iran does, North Korea is watching to see: 'is this just U.S. talking tough but doing nothing, and we can get away with this, or are there really consequences for these aggressive actions.'"
Iran also is believed to be developing a nuclear weapon capability, although it says its nuclear program is only for peaceful purposes like generating electricity.
The U.S. is working with the United Nations Security Council to try to reach a diplomatic solution with both Iran and North Korea.
The Council has passed sanctions against both Tehran and Pyongyang in the past, but they have had little apparent effect.
In the case of North Korea, one reason may be that its recent show of force may be driven more by internal politics, than international considerations. Some analysts say leader Kim Jong Il, who appears to be ailing, wants to ensure the military supports his successor.
As for Iran, the leadership's motives may be more mixed. U.S. foreign policy expert Flynt Leverett says Washington needs to do more to reassure Iran, because despite President Obama's calls for improved relations, Tehran believes the U.S. is still pursuing the policy track of former President Bush.
"What I'm concerned about is that the promise of this early rhetoric will be undermined by this lack of new initiatives, and particularly if the administration continues to try and use its professed willingness to engage Iran, to muster more international support for intensified sanctions, I think that's going to undermine the credibility of any diplomatic initiative," he explained.
But others are calling for a much harder line. Retired Air Force Lieutenant General Thomas McInerney says if diplomacy fails with Iran and North Korea, the U.S. may have to take out their nuclear sites.
"Because I believe that the ability for Iran to give radical Islam terrorists a nuclear weapon or weapons, because it will be more than one, is increasing dramatically," he said.
But Scheber says military action is not necessary, as long as a strong missile defense system is maintained. He says the Obama administration's recent decision to cut missile defense spending should be reconsidered.
"Failure to do so could unleash this cascade of proliferation and act against the very forces of controlling proliferation that we seek to keep under control," he added.
In Prague earlier this year, President Obama pledged to lead a global effort to limit the spread of nuclear weapons. How he responds to North Korea and Iran, experts say, may indicate how effective those efforts will be.