Defence Minister Peter MacKay might want to give his old Grade 5 geography teacher a call for a brush-up.

MacKay made a bit of a gaffe Tuesday night, when he stated British Columbia shares a border with California when he posed a question to the state's former governor, Arnold Schwarzenegger.

The "Terminator" actor politely quipped that Oregon and Washington happen to exist between B.C. and the Golden State.

MacKay, a politician not generally prone to brain hiccups, was spared no quarter on Twitter, as his name began trending Wednesday.

"The UAE dispute could have been resolved but ultimately Peter MacKay decided we didn't need a base in South America," Macleans scribe Scott Feschuk tweeted.

"Breaking: Peter MacKay reveals part of the Conservatives hidden agenda. Annexing Washington State and Oregon!" another Twitter user, Albertaardvark, joked.

Schwarzenegger was speaking in Winnipeg Tuesday as part of a cross-country Canadian tour.