Gary Johnson. Screenshot via MSNBC Libertarian presidential nominee Gary Johnson said he was having an "Aleppo moment" when he was unable to name a favorite foreign leader during an interview on MSNBC on Wednesday night.

Host Chris Matthews asked Johnson, who was sitting with his running mate, Bill Weld, to pick one foreign leader whom he looked up to.

Johnson struggled to answer, and Weld swooped in.

"Mine was Shimon Peres," Weld said, naming the former Israeli prime minister and president who died Tuesday.

"I'm talking about living," Matthews quipped, pointing back to Johnson who sat quietly.

"You gotta do this," Matthews goaded. "Anywhere. Any continent. Canada, Mexico, Europe, over there, Asia, South America, Africa: Name a foreign leader that you respect."

"I guess I'm having an Aleppo moment," Johnson responded, adding that he was having trouble thinking of the name of one of the former presidents of Mexico.

Johnson was alluding to another awkward situation from earlier this month, in which Johnson asked "What is Aleppo?" during another interview on MSNBC. Aleppo is the site of some of the fiercest fighting in Syria's civil war.

Since then, Johnson's foreign-policy knowledge has come under fire.

Pressed by Matthews again on Wednesday night, Johnson reiterated his answer, "The former president of Mexico."

"Which one?" Matthews asked.

"I'm having a brain freeze," Johnson said, as his running mate began to list the names of recent Mexican presidents: "Fox, Calderon ..."

"Fox! Thank you!" Johnson shouted out, referring to Vicente Fox, who served as Mexico's president from 2000 to 2006.

Watch the exchange below:

