By any measure, Donald Trump is the most controversial US President of the modern era. With his promise to `Make America Great Again', he's leading an onslaught against many of the checks and balances that lie at the very heart of the US Constitution, and he's dramatically diminishing America's historic global standing in the process.

He's waged war against the media, raged about the country's judiciary, diminished and undercut political leaders at home and overseas, and his relentless and irresponsible use of social media has created a cycle of non-stop chaos in Washington.

So why would anyone accept an invitation to join his extreme administration? How have the President's aides and Cabinet members navigated the moral maze necessary to come to terms with his rule? And what long-term consequences will be faced by those men and women who have put their own reputations on the line in order to carry out his instructions?

The Trump presidency is like no other, and in Trump's Willing Executioners: Choosing to Serve America's 45th President, veteran Washington correspondent Simon Marks looks at the extraordinary cast of characters who have willingly signed up. Meet the ideologues, chancers, enablers, spinners, thugs and even some genuine public servants who have thrown their hat into President Donald Trump's ring.