Donald Trump's role in the GOP primary this election cycle is an example of what I call the "Assholes & Idiots Theory of Politics." The Assholes & Idiots Theory says, quite simply, that in any political organization of sufficient size - political party, legislature, campaign, etc., there will be a certain number of people who are assholes and a certain number of people who are idiots, and one job of the leader(s) of that organization is to contain the assholes and idiots. Different leaders have different approaches, but all have to use some kind of moral authority . Ronald Reagan was able to successfully contain the assholes and idiots because he had a great deal of credibility as a leader of the conservative movement. So Reagan is still revered by conservatives, despite occasionally compromising with Democrats or raising taxes. Bill Clinton was able to straddle the progressive and moderate wings of the Democrat party because he understood the appeal and perspectives of both, so he was able to promote a pro-business agenda (free trade) and enact fairly liberal legislation (raising taxes on the rich). Clinton's success at containing the assholes and idiots laid the groundwork for the successful presidency of Obama, who, again, straddles the progressive and moderate wings of the Democrat party. Obama's status as the first black president also gives him enormous moral authority, which he has used very adroitly.
George W. Bush, on the other hand, spectacularly failed to contain the assholes and idiots within his party, starting with his vice president. There's a simple and obvious reason why Bush failed to do so: he's both. Bush's failure in this respect had the opposite effect that Clinton's success did. Instead of laying the groundwork for another politician who could contain the assholes and idiots, Bush created an opportunity for the ultimate asshole and idiot, Donald Trump, to take the GOP by storm.
Containing assholes and idiots is never easy, particularly because they rarely think of themselves in those terms. They think of themselves as passionate and dedicated advocates for their cause. They don't think of themselves as deluded narcissistic whack jobs whose refusal to compromise or even acknowledge the validity of other voices is an expression of unbridled anger and pain. Ideally, the successful leader will acknowledge their pain, their anger, their experience, and their perspective, give them enough to alleviate the pain and make them feel like they are being heard and their problems are being addressed. Or, in a less-than-ideal situation, a leader will discredit them and their ideas and marginalize them, walling them off in some obscure corner of society where they spend their lives venting their frustrations in the company of people who agree with them.
Rather than co-opt or marginalize the assholes and idiots, Bush put them in positions of power, gave them almost everything they wanted, and let them wreak havoc. When they failed, as in Iraq and in the economy, he refused to even consider the possibility that the assholes and idiots he had unleashed had any responsibility for the disasters they had created. Bush didn't just fan the flames of anger; he threw gasoline on the fire. Trump then proceeded to build other fires, and then throw gasoline on them.
Now there isn't anyone strong enough to contain Trump, although some are trying. Paul Ryan, to his credit, is using his new authority as Speaker of the House to denounce Trump's bigotry in clear and concise terms.
It is not merely for the good of a particular organization or party that the assholes and idiots must be contained. To contain the assholes and idiots is the essence of the democracy and the democratic project. Regardless of the strength or moral clarity of certain politicians, the saving grace of the need to contain the assholes and idiots comes down to one thing: in the end, democracy always wins. The process may be ugly, it may be disheartening and leave many with scars, but no one ever said democracy would be easy. In the end, democracy ultimately rewards those who can not merely articulate their own ideas, but those who can also listen and respect those they disagree with. Which is one thing Donald Trump, the ultimate asshole and idiot, clearly does not understand.