Former CIA director John Brennan had a fraught relationship with US President Donald Trump, and now he remains one of Trump's sharpest critics.
In his new memoir, 'Undaunted, Brennan told Business Insider what he feels is the biggest threat to the November election: President Trump himself.
Brennan says the Trump administration and campaign's 'dishonesty' and disinformation is just as dangerous as foreign interference in the election.
He added that Trump's refusal to acknowledge Russia's interference in the 2016 election would become one of the defining failures of his presidency.
On the other hand, Brennan said Russia has gotten everything it could have hoped for from the Trump presidency.
