It was a retort perhaps only one American politician could have produced, and one that silenced the room.
Faced with a determined heckler during a campaign rally for Hillary Clinton, Joe Biden reached for a very personal response in Cleveland on Thursday.
“My friends died, my American friends,” the heckler was shouting, remonstrating with the vice-president over US policy in Syria.
“My friend died,” he repeated, challenging Mr Biden to explain his recent demand that Kurdish allies withdraw from captured Islamic State territory.
Interrupted again while trying to explain the complex Middle East policy, something snapped on stage after the third shout of “my friend died”.
“Will you listen? So did my son, OK?” shot back the vice-president, instantly silencing both the heckler and those in the crowd who had been trying to drown out the disruption by shouting: “Hillary, Hillary.”
Mr Biden’s son Beau, an Iraq war veteran and former attorney general of Delaware, died of cancer last year at the age of 46.
The vice-president’s very public grief over the loss – of a son he raised alone after Beau’s sister and mother were killed in a car accident in 1972 – moved much of the nation.
Both Mr Biden and US president Barack Obama have said it was a major factor in the vice-president's decision not to seek the Democratic nomination for the White House this year. But in a union hall outside Cleveland, campaigning for his party's nominee, the rawness of the grief was still apparent.
It could have been a convenient non-sequitur, or just a simple unfiltered moment of exasperation – but in any event the protestor appeared satisfied with a promise to discuss the matter in private after the rally.
“Look let me answer your question. Come back after and talk to me about this. OK? You have my permission,” finished Mr Biden.
Shortly afterwards the man could be seen talking to secret service agents and appearing to head to a backstage area.
The protestor was referencing a controversial US decision to force the victorious Kurdish YPG forces to withdraw from the captured town of Manbij to the other side of the Euphrates river – a move aimed a placating Turkey, which views them as terrorists.
“Why did you tell the YPG to go back?” he shouted at Mr Biden, who intervened during a recent visit to Turkey.
“Because the deal was to get them into Manbij – and to work – was that they would go back across the Euphrates so we could have [US]special forces move in. That’s why,” responded the vice-president.
There are reports that three Americans died alongside the YPG in Manbij, part of a group of foreigners who travelled to Syria to fight against Islamic State, also known as Isis.
AP