In this episode of Head to Head, Mehdi Hasan challenges former Trump campaign national security director, JD Gordon, on allegations of collusion with Russia, the US president's foreign policy agenda and what it was like to work for the former reality TV star.

While advising Donald Trump, Gordon helped craft the president's national security and foreign policy agenda.

He has been subject to the investigation of the Russian government's alleged interference in the 2016 US presidential election.

On this matter, he has testified before the Department of Justice and in front of congressional intelligence committees.

We challenged Gordon on everything from the president's reported falsehoods to North Korea, Iran and the Trump Tower meeting between top Trump aides and Russian lawyer Natalia Veselnitskaya in 2016.

Before working with Trump, Gordon served as a Pentagon spokesman, a campaign adviser to two other Republican presidential candidates and worked under defence secretaries Donald Rumsfeld and Robert Gates.

He also spent 20 years in the US Navy and is now a regular contributor to Fox News and The Washington Times, among others.

During the exclusive interview, we also asked Gordon about Trump's understanding of complex foreign policy issues, his perceived hostility to foreigners and, if nearly two years after working on Trump's campaign, he still stands by the president.

We are joined by a panel of three experts:

Ellie Geranmayeh, senior policy fellow for the Middle East and North Africa Programme at the European Council on Foreign Relations

David Cay Johnston, Pulitzer-prize-winning journalist and the author of The Making of Donald Trump; and It's Even Worse Than You Think: What the Trump Administration is Doing to America

Marc Porter, adviser to the Trump/Pence 2020 re-election campaign and president of Republicans Overseas France

Trump: Global threat or new world order? with JD Gordon will be broadcast on July 27 at 20:00 GMT and will be repeated on July 28 at 12:00 GMT, July 29 at 01:00 GMT and July 30 at 06:00 GMT.

Head to Head is Al Jazeera's forum for ideas, a gladiatorial contest tackling big issues in front of an opinionated audience at the Oxford Union.

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