"Here's a good one. Helen Clark, former prime minister of New Zealand: her opponents have observed that in the event of a nuclear war, the two things that will emerge from the rubble are the cockroaches and Helen Clark. [Laughs]"
Setting Hillary's sense of humor aside for a moment (the joke doesn't get funnier even if you happen to know something about New Zealand politics) Helen Clark is the current prime minister of New Zealand.
The diplomatic ramifications of this become even more dire when you consider that New Zealanders have been somewhat skeptical about Hillary Clinton ever since she met Sir Edmund Hillary, the first mountaineer to climb Everest, and mentioned that she had been named after him. It was later pointed out that Sir Edmund climbed Mt Everest six years after Hillary Clinton was born.It appears that the local press is more indignant about Hillary calling Clark the "former" prime minister than the suggestion that Clark is a cockroach. You can read local press reactions here and here.
Photo from Flickr user lestath_x under a Creative Commons license.