Alan Dershowitz: 'There is no such thing as truth any longer'

Professor Alan Dershowitz has been called the best-known criminal lawyer in the world.

He has just retired from Harvard University Law School, after 50 years, and has led a high profile career in academia, constitutional and criminal law, fiction writing and as a media personality.

He's represented a series of celebrity clients, including Mike Tyson, Patty Hearst, Jim Bakker, Klaus von Bulow and was part of the OJ Simpson so-called "dream team".

Dershowitz is a staunch supporter of the Democratic Party, and has surprised many with his view that there is no case for obstruction of justice charges to be brought against President Trump.

"I've lost 7 pounds on my Trump diet," he says. "My liberal friends don't invite me to dinner any more."

His latest book is called Trumped Up: How Criminalization of Political Differences Endangers Democracy and he says discourse and debate have disappeared from American life.

"There has never been a time in American history like this where we have such unpredictability and such division.

"There is no such thing as truth any longer. In dialogue there is a Republican truth, there's Democratic truth, there's Trump's truth, there's anti-Trump truth - nobody is listening to the other side.

"The right is moving further right to the old right, the left is moving further left toward the hard left and the centre is suffering, and it is the centre that lends stability to any nation."

Dershowitz says he craves what he calls the "good old days" of debate.

"I used to debate people like [conservative author] William Buckley. You'd have a liberal debating a conservative and people would really listen.

"Today there's no debate, there's just shouting matches; the presentation of one side to an echo chamber and the other side to an echo chamber, and never the twain shall meet."

He believes the US could learn from countries such as New Zealand where he says there is a higher level of debate.

He has provoked the ire of his fellow liberals by stating there was no strong legal or constitutional grounds for removing President Trump.

"It's easy to impeach, it's almost impossible to remove."

Dershowitz says the 25th Amendment, which allows for the removal form public office on the grounds of mental or physical incapacity, was designed for extreme cases.

"It was not intended to rid the country of an eccentric president or a president who doesn't play by the rules or who some psychiatrists believe has a narcissistic personality."

Impeachment is also next to impossible, he says.

"There'd be no chance of getting the two thirds [Senate vote] that is required for removal from office."

As to any murky dealings in Trump's business life leading to his resignation to avoid prosecution Dershowitz says, "That is a conceivable scenario, but I think extremely unlikely."