Joe Biden used the memory of his late son in response a protester who said his friend died fighting ISIS.

The vice president shut down the demonstrator during a Hillary Clinton town hall event in Cleveland, Ohio, with four unexpected words: 'So did my son.'

The Democrat then invited the protester, who said his friend was killed while serving for the Kurdish Forces in Syria, backstage to talk privately after his speech.

He was talking about Trump’s plans to lower taxes on the ultra-wealthy when the man in the back of the room started shouting.

'So did my son!' This is the moment Joe Biden used the memory of his late son to shut up an Iraq War protester who said his friend died while serving in the military

'Some of my friends, my American friends died,' the protester said. 'Why did you tell the YPG to go back across the border.'

The unidentified protester was referring to the mission to liberate the Syrian city of Manbij.

Biden responded: 'Because the deal was to get them into Manbij and to work they had to go back across the Euphrates so we could have special forces move in that’s why.'

The man continued his criticism about his friends in the military, so Biden addressed him directly and said: 'So did my son.'

His son Beau served in the US military for 12 years. He died on May 30, 2015, after battling brain cancer for two years.

The man identified himself as a veteran of the Kurdish armed forces and said his friend Levi Shirley was fighting ISIS when he died.

Shirley, a 24-year-old Colorado native, was killed by a landmine in Syria this July.

Biden lashed out at Trump during the remainder of the speech that cast the Republican presidential nominee as the enemy of working men and women.

He said the Republican candidate's foot is in his mouth so often that he's choking on his silver spoon.

While Trump was in southern Ohio delivering an uncharacteristically short stump speech that lasted just 22 minutes, the gaffe-prone Biden played kettle-and-pot with foot-in-mouth Trump in the rust belt town of Warren in the state's northeast.

The Democrat then invited the protester, whose friend died fighting in Syria, backstage to talk privately after his speech

Biden's son Beau (left) served in the US military for 12 years. He died on May 30, 2015, after battling brain cancer for two years. The pair are pictured together in Baghdad, Iraq, in 2005

Complaining about Trump's contention in a November 2015 Republican primary debate that America's 'wages are too high,' Biden said the billionaire was too rich to know what he was talking about.

'This is a guy born with a silver spoon in his mouth that he's now choking on,' he said, 'because his foot's in his mouth along with the spoon!'

The vice president is himself known as a one-man gaffe factory, generating more headlines for his missteps than for his contributions to the Obama administration.

On Thursday Biden was all business, however.

'American workers are three times as productive, by any study, as Asian workers are,' he claimed.

The man identified himself as a veteran of the Kurdish armed forces and said his friend Levi Shirley (above) was fighting ISIS when he died. Shirley, a 24-year-old Colorado native, was killed by a landmine in Syria this July

'I'm so sick and tired – I know I'm not supposed to get angry – but I'm so sick and tired of hearing people like Trump and the Chamber of Commerce, the national Chamber, talking about "We get paid too much," that we don't want to – give me a break! Give me a break.'

Trump's debate line 10 months ago concerned America's lack of competitiveness in global manufacturing markets.

'We have to become competitive with the world,' he said then. 'Our taxes are too high, our wages are too high, everything is too high.'

That, his aides hinted later, indicated that he thought Americans shouldn't take home less money from their paychecks – only that government should get a smaller cut.

Biden's history of embarrassing misstatements is legendary in U.S. political circles, making his criticism of Trump a feast of irony.

At 2014's U.S.-Africa Leaders Summit, he declared his support for the 'nation' of Africa – a continent.

Biden also slammed Trump's plan to lower taxes on the ultra-wealthy. He said: 'This is a guy born with a silver spoon in his mouth that he's now choking on'

​'There's no reason the nation of Africa cannot and should not join the ranks of the world's most prosperous nations in the near term, in the decades ahead. There is simply no reason,' he told heads of state and other dignitaries.

The skinny-dipping, party guest-groping bumbler who's one heartbeat away from the presidency once chaired the U.S. Senate Committee on Foreign Relations.

It was just six years ago that he noted in a diplomatic face-palm moment how Irish Prime Minister Brian Cowen's mother had 'lived in Long Island for ten years or so' before her death.