Barack Obama says the European Union doesn't moderate British influence but it "magnifies it".
The US President strongly feels the United Kingdom is better off staying within the European Union, and made this clear as he visited London to attend Queen Elizabeth's 90th birthday celebration.
His message on the EU vote is annoying some in an increasingly fractious debate in the UK, and it seems to reflect bigger fears that Europe is vulnerable.
Home-grown attacks, the refugee crisis and the rise of the far-right all threaten to undo unity on the continent.
Obama is hoping he can convince Europeans they're better off together.
Where would a UK exit from the EU leave Western power on the global scene?
Presenter: Sami Zeidan
Jeremy Shapiro - Research Director at the European Council on Foreign Relations.
Thorsten Benner - Director of the Global Public Policy Institute.
Alan Mendoza - Founder and Director of the Henry Jackson Society.
Source: Al Jazeera