There's a fierce debate about whether it's ethical for mental health professionals to diagnose politicians they haven't personally examined.
The Republicans' hardline 1964 candidate famously said that 'extremism in the defence of liberty is no vice'. Sound familiar?
The leading conservative magazine National Review has played a critical role in creating modern GOP. Their repudiation of Trump signals crisis for Republicans.
In 1964, the John Birch Society pushed Barry Goldwater to victory in the Republican primary. The same could happen with the Tea Party and Trump this election cycle.