Libertarian Party presidential candidate Gary Johnson tried to explain away a mortifying gaffe about the Syrian city of Aleppo on Thursday as having 'blanked'.

He was given a brutal education on the Middle East as he was asked on MSNBC's Morning Joe: 'What would you do, if you were elected, about Aleppo?'

Johnson, a former governor of New Mexico, first asked 'about?' then stared ahead silently but his deer-in-headlights expression spoke volumes.

'And what is Aleppo?' he finally asked.

'You're kidding,' MSNBC contributor Mike Barnicle deadpanned. 'No,' came a reply from Johnson.

THIRD-PARTY FAIL: Libertarian presidential nominee Gary Johnson stared into space when an MSNBC political panelist asked him what he would do about Aleppo, without telling him what it was ahead of time

'YOU'RE KIDDING': Journalist Mike Barnicle couldn't believe a presidential candidate didn't know the significance of Aleppo, the epicenter of the Syrian refugee crisis

'WHAT IS ALEPPO?' An elderly Syrian man and a child walk through a field of debris in what was once a residential neighborhood after a government-dropped barrel bomb hit it in 2014

Barnicle had asked Johnson what he would do about Aleppo if he were elected, but didn't offer any context that might help the long-shot candidate decipher what was being asked.

Eventually, he needed some help.

'Aleppo is in Syria. It's the epicenter of the refugee crisis,' Barnicle offered.

'Okay, got it. Got it,' Johnson said.

In a hallway interview with Bloomberg Politics following his cringe-worthy 'Morning Joe' moment,' Johnson said he was 'incredibly frustrated with myself.'

'I have to get smarter,' he said. 'That's just part of the process.'

'WHAT IS ALEPPO?' This photo from Aug. 31 shows children in the Syrian city swimming in a hole made by a missile attack

In a statement, the Libertarian Party nominee said: 'This morning, I began my day by setting aside any doubt that I'm human.'

'Yes, I understand the dynamics of the Syrian conflict – I talk about them every day. But hit with "What about Aleppo?", I immediately was thinking about an acronym, not the Syrian conflict.'

'I blanked,' Johnson added. 'It happens, and it will happen again during the course of this campaign.'

He also suggested that he would rely on aides and advisers to keep him current on world affairs, if he should win the White House.

'As Governor, there were many things I didn't know off the top of my head. But I succeeded by surrounding myself with the right people, getting to the bottom of important issues, and making principled decisions. It worked,' he said.

He then went on The View on ABC and was questioned again on the gaffe, repeating his claim: 'I was thinking in terms of acronym Aleppo.'

Hillary Clinton chuckled about Johnson's gaffe a few hours later during a brief media availability on an upstate New York airplane tarmac.

'Well, you can look on the map and find Aleppo!' she said.

'WHAT IS ALEPPO?' This mid-August image of a five-year-old boy in Aleppo shows him shell-shocked after he was pulled out of a building's rubble following a Syrian government airstrike

'WHAT IS ALEPPO?' Soldiers belonging to the Free Syrian Army are seen during an anti-ISIS operation last week

Johnson has been polling in the high single-digits in most national election surveys but a few polls have him reaching as high as 12 per cent.

He is running with former Massachusetts governor William Weld.

Johnson finally pronounced Syria's protracted and violent civil war 'a mess.'

'And I think the only way that we deal with Syria is to join hands with Russia to diplomatically bring that at an end,' he said.

'But when we've aligned ourselves with, when we've supported the opposition, the Free Syrian Army – the Free Syrian Army is also coupled with the Islamists – and then the fact that we're also supporting the Kurds, and this is, it's just a mess.'

'And this is the result of regime change that we end up supporting and, inevitably, these regime changes have led to a less safe world.'

'DEPRESSING

Barnicle's full question was: 'What would you do, if you were elected, about Aleppo?'

MSNBC co-host Joe Scarborough was flabbergasted at the answer and asked Johnson if he believed 'foreign policy is so insignificant that somebody running for president of the United States shouldn’t even know what Aleppo is, where Aleppo is, why Aleppo is so important?'

Johnson tried to salvage a rapidly deteriorating situation.

'I do understand Aleppo and I understand the crisis that is going on,' he said. 'But when we involve ourselves militarily, when we involve ourselves in these humanitarian issues, issues, we end up with a situation that in most cases is not better, and in many cases ends up being worse.'

'And we find ourselves always – politicians are up against the wall, and ask what to do about these things, and this is why we end up committing military force in areas that, like I say, at the end of the day have an unintended consequence of making things worse.'

MAYBE NOT: 2012 Republican presidential nominee Mitt Romney said Wednesday on Twitter that Johnson should have a more visible role in the election

'Boy, that’s depressing,' Scarborough said later.

'It is staggering that somebody would run for President of the United States, get 14 per cent, 15 per cent in polls, and be so ignorant on foreign policy they would ask the question "what is Aleppo?" on national television.'

'I was stunned,' Barnicle offered. 'It's been on the front page of every newspaper for months.'

Former Republican presidential nominee Mitt Romney tweeted on Wednesday that Johnson and his running mate should be given greater visibility during the final months of the election season.