New Zealand's 25 years of nuclear freedom have not often made the country the toast of international state conferences, but it appears to have helped get the Prime Minister a seat at the Nuclear Security Summit in South Korea that concluded yesterday.
Mr Key used the opportunity to pursue free trade talks with the hosts, treat his embattled Australian counterpart, Julia Gillard, to a glass of New Zealand pinot noir and eventually catch a moment with President Barack Obama.
He was also able to explain in person to the President of Finland his minister Gerry Brownlee's observations on that country in Parliament last week. Mr Key was far from home when the police decision on his teapot case was made public, but in Seoul he was well placed to observe how Mr Obama handled a "hot mic" problem.
When the President's conversation with Russia's Dmitry Medvedev was recorded by a reporter, the White House did not try to suppress the mildly embarrassing contents. It simply weathered the fact that Mr Obama told Mr Medvedev he would have more "flexibility" on the contentious missile shield after the United States elections.
If the news from the summit took some time to reflect the importance of its purpose, so did the discussions in the room. The 53 leaders gave priority to the immediate issues of Iran's nuclear developments and North Korea's stated intention to send a missile into space next month.
When they eventually turned to the subject of securing nuclear materials against terrorism they produced little beyond worried resolutions.
Mr Key in his closing remarks said a nuclear terrorist attack would have more impact even than 9/11 on every country in the world and in that event, this week's summit would be called to account.
His warning was endorsed by President Obama.
The spectre of nuclear terror has been haunting the world ever since nuclear proliferation extended to states such as Pakistan and North Korea, and particularly since the breakup of the Soviet Union.
A group who came into possession of frighteningly small quantities would not need to detonate it to cause havoc, even greater terror could result from a credible threat to use the material unless impossible demands were met. A former US presidential candidate, Senator John Kerry, used to call it the gravest threat to the security of all countries and President Obama, since his election, has tried to put it high on the international agenda.
In 2010, he hosted a Nuclear Security Summit in Washington which New Zealand attended.
Economic worries in the wake of the global financial crisis left little room for world leaders to concentrate on much else. They agreed on a goal to secure the world's nuclear materials in four years.
Two years on, Mr Obama believes they are making progress. "We are improving security at our nuclear facilities. We are forging new partnerships. We are removing nuclear materials, and in some cases, getting rid of these materials entirely," he said at the start of the second summit this week.
At the end of it they set a target of 2014 for their countries to adopt a convention that would minimise the use of bomb-grade highly enriched uranium in nuclear reactors.
Some of them pledged to eliminate their stocks of fissile material and the US, France, Belgium and the Netherlands agreed to produce medical radioactive isotopes without highly enriched uranium.
New Zealand contributed $500,000 to the removal of nuclear material from Uzbekistan.
These are not small steps, said Mr Obama's Energy Secretary, Stephen Chu. "A lot is happening, the world is becoming a safer place."
May it be so.