The electorate of the United States is so closely divided and the two major candidates so objectionable to the other camp, that the 2016 Presidential election is bound to be close. The number of voters who can be swayed, despite the billions to be spent on their persuasion, is probably not enough to decide the outcome of the election.
What may well defeat Trump is the elite of his party, particularly the Bushes.
Many Republican elected, economic, foreign affairs, and military leaders believe Hillary Clinton more closely adheres to their worldview on trade and security than does Donald Trump.
While the Republican elite might not vote for Hillary, they may well not vote for Trump.
To persuade reluctant Republicans to vote for Trump the U.S. Senate refused to consider the appointment of Merrick Garland to the Supreme Court and Ted Cruz was allowed to speak at the convention to implore Republicans not to stay home.
That Trump recognizes how implacable the Republican leadership who did not attend the convention is evidenced by his making no overtures in their direction as he did to religious groups in his convention speech.
The often referenced Trump as strongman is bolstered by his elimination of all who oppose him. Trump has not and will not eliminate the opposition of the Bush clan.
The Bush-Trump war will be one of the most consequential battles of the 2016 Presidential campaign. The Bush grievances against Trump extend not only from their contrary worldviews of traditional Republican positions, but to a personal vendetta from the trashing of Jeb, Trump’s easy dispatch of the $130 million dollars Bushes supporter put up in the primary to support Jeb, and most personally egregious–the mocking of matriarch Barbara Bush.