But he could not name a world leader or knew about Aleppo. Libertarian candidate Gary Johnson had another tough night on the campaign trail when he couldn't come up with the name of a foreign leader during an interview Wednesday.

"Who's your favorite foreign leader," MSNBC's Chris Matthews asked Johnson, who sat beside his running mate, former Massachusetts governor Bill Weld.

Matthews pushed Johson to pick anyone, from any continent or country, after an apparently confused Johnson repeated the question.