Jean Chrétien and Bob Rae are both former leaders of the Liberal Party of Canada. Something else they have in common: They like to choke each other.
Rae later returned the favour, sneaking up on Chrétien at dinner and choking him from behind.
Chrétien and Rae's choking gag is a reference to the famous "Shawinigan Handshake" — when, as prime minister, Chrétien choked an anti-poverty protester who got in his way.
Chrétien never apologized for the incident, and he has made light of it in the years since. Although his actions were deemed "un-prime ministerial" at the time, he was given a pass by the public because a knife-wielding intruder had broken into his home just months earlier. So it wasn't unfathomable that he might be somewhat jumpy.