Updated at 2:30 p.m. ET
Asked to name his favorite foreign leader, or any foreign leader he admires, Libertarian nominee for president Gary Johnson was unable to come up with an answer.
The exchange occurred on an MSNBC town hall hosted by Chris Matthews Wednesday night.
When Johnson hesitated at the initial question, Matthews said, "Go ahead, you gotta do this. Anywhere. Any continent. Canada, Mexico, Europe, over there, Asia, South America, Africa. Name a foreign leader that you respect."
Johnson: I guess I'm having an Aleppo moment in 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: Which one?
Johnson: I'm having a brain ... "
Johnson's running mate, vice presidential nominee Bill Weld, sat next to him and eventually jumped in to offer the name of former Mexican President Vicente Fox.
Johnson weighed in Thursday on Twitter:
On Facebook, Johnson/Weld campaign manager Ron Nielson responded:
"Yes, asked to name a favorite foreign leader, Gov. Johnson didn't quickly name a specific favorite. That really doesn't mean much. Most Americans and certainly most political candidates would have to stop and think before responding, with the possible exception of a Donald Trump who is enthralled by Putin."
This is Johnson's second major flub on foreign policy this month. On Sept. 8, on MSNBC's Morning Joe, he asked "What is Aleppo?" As NPR's Scott Horsley wrote, the instance betrayed a stunning lack of interest or even superficial knowledge of the civil war in Syria that has been raging for more than five years.
On Thursday, Johnson picked up an endorsement from the Detroit News. It's the first time since the paper's founding — 143 years — that it has endorsed a candidate other than a Republican.
"Gary Johnson best matched the values of this newspaper," said editorial page editor Nolan Finley in a video posted on the site.
"This is an endorsement of conscience," the editorial reads, "reflecting our confidence that Johnson would be a competent and capable president and an honorable one."
Green Party presidential nominee Jill Stein tweeted out a list of people she admired, though as Politico and several people on Twitter noted, none are leaders of their respective countries.