Libertarian presidential candidate Gary Johnson couldn’t name a single world leader he admires in a painfully embarrassing exchange during a live MSNBC town hall aired Wednesday night.

Pressed by MSNBC’s Chris Matthews to pick one leader he respected from anywhere in the world, Johnson froze up and said he couldn’t do it. He then admitted to having an “Aleppo moment” — a reference to when Johnson copped to not knowing the Syrian city during an interview on MSNBC.

Here’s the deer-in-the-headlights moment:

When Johnson first deflected the question, Matthews said, "Go ahead: You got to do this. Anywhere. Any continent. Canada, Mexico, Europe, over there, Asia, South America, Africa. Name a foreign leader that you respect."

The exchange continued:

JOHNSON: I guess I'm having an Aleppo moment ... the former president of Mexico. MATTHEWS: But I'm giving you the whole world. JOHNSON: I know, I know, I know. MATTHEWS: But I'm giving you the whole world. Anybody in the world you like. Anybody. Pick any leader. JOHNSON: The former president of Mexico. MATTHEWS: No — Which one? JOHNSON: I'm having a brain..."

At that point, Johnson’s running mate — former Massachusetts Gov. Bill Weld — intervened and started naming former Mexican presidents like Vicente Fox.

Matthews then posed the initial question to Weld, and Johnson’s No. 2 quickly produced an answer: Weld said he admired German Chancellor Angela Merkel.

As Weld spoke, Johnson’s eyes drifted downward, and he looked at the floor.