Basically, the US right has been taken over by a ranting minority who have realised they rouse more support with lies and distortions than with could with reasoned, fact-based argument. It's no coincidence the GOP is seen outside the US as the party of the willfully ignorant. Margaret Thatcher was pretty clear about her support for - and strong ties with - the GOP, back in her day: last time around, even her party was praying for an Obama win (though they couldn't say so, of course).
There are sensible, thoughtful - even compassionate - people on the right, but they've been ousted, silenced or forced into conformity by the extremists who are driving their cause into political obscurity and irrelevance.
Look at Mitt Romney: in theory, he should have been a great candidate: he
was a moderate conservative with a decent record who ought to have been able to win support in blue states in possibly the most win-able election for the GOP since Reagan faced Carter. Sadly for the GOP (but happily for the world
), the raving right forced Romney to reinvent himself as an extremist in their image to win the nomination and consequently, he was
annihilated in the election.