What Do these Men Have In Common?

They were both Democratic Presidents When Canada has a Conservative Prime Minister.

• Joe Clark served as Canada's 16th Prime Minister from 1979-1980
• Stephen Harper is the current and 22nd Prime Minister
• Jimmy Carter was the 38th President of the USA, from 1977-1981
• Barack Obama will be the 44th President and is the President Elect

There has been exactly 6 prime ministers and 6 presidents since the last time this political anomaly occurred. Coincidence, I think Not :)