Will the political talk settle down?

It would be a good thing if the divisive political talk, centered at first around Donald Trump but now spreading to other candidates, would settle down.  It is said "other candidates", as in the debates Bernie Sanders is somewhat restrained, but his campaign is massively anti-business, as in making money for shareholders has acquired an evil taint.  God knows, the system is not perfect but someone please find a better one in a country bigger than Sweden.

Trump's ongoing domination of the Republican dialogue is unfortunate, as this could have been a year of substantive debate between the two parties.  Now the Republicans have mostly gone to the edge, and those with the slightest bit of moderation, Rubio, Bush, and Paul, are being tormented by the extremist ring of the so-called "Party".  Cruz is by far the most dangerous person out there, from this, of course, completely unbiased point of view.  The damage he will do as a candidate, even if he loses, will be unprecedented for the U.S. political system.  He does not care at all what damage he causes.  He is a political nihilist.  Who could this remind one of?  In the distant past?  In what country?