There are three ways Hillary Clinton can be defeated by Donald Trump in November.
It was always assumed that a terrorist attack on America's shores would boost the Republican nominee. Surely it would have, if that nominee's name weren't "Trump," a clearly unsteady hand. Democrats should shudder at the thought of the political benefit which would have accrued to a Marco Rubio, Ted Cruz, even a Chris Christie with the terrorist attack in Orlando. Though Trump squandered his recent opportunity with irresponsible rhetoric, it is likely that terrorist groups in the Mideast would welcome his election (video below) and act accordingly.
A searing report from the FBI about Secretary of State Clinton's private e-mail server also would be politically damaging and in the unlikely charges were recommended, perhaps fatally so.
There is a third, completely ignored, path to victory for Mr. Trump. Politico reports that Clinton led Trump by five points in the most recent CNN/ORC poll but that her lead dipped to four points when Libertarian Gary Johnson and Green Jill Stein were included.
That is not a huge drop, nor are the two likely to poll in total in November the 16 points they did in the latter survey. Nonetheless, the inclusion of either or both (especially Stein, who would take mostly Clinton voters) in one or more presidential debates would be highly problematic for any candidate facing Donald J. Trump.
Out of the corner of his eye, Paul Krugman evinced a little of the truth about the GOP primary race when, assessing the difference between the two political parties, he noted
.....the Democratic establishment in general is fairly robust. I’m not saying that its members are angels, which they aren’t. Some, no doubt, are personally corrupt. But the various groups making up the party’s coalition really care about and believe in their positions — they’re not just saying what the Koch brothers pay them to say.
If the GOP establishment really doesn't believe the Koch brothers but merely is responding favorably to them out of political necessity, it would explain a fair chunk of the inability to coalesce around an alternative to Trump, widely regarded as an apostate to the conservative, Republican cause. (He's beginning to get onboard now, partly by pleasing the RNC by firing Corey Lewandowski.)
Disregard all of the other explanations for Trump's conquest. He was the loudest mouth, the most glaring demagogue, the individual who most viscerally hated forces hated by conservatives, and he kept repeating "poltical correctness." He stood out, literally and figuratively, against the others. In a two-way race against Marco Rubio, Ted Cruz, Chris Christie, even John Ellis Bush or the most loathsome human being in America, Donald Trump would have been defeated. Response to Trump's personal insults was belated and half-hearted because a more robust defense or attack would have hurt both candidates. In a two-way race, that might have been strategically advantageous.
Tired of waiting for his one-on-one matchup with the real estate guy, Ted Cruz dropped out during his own concession speech after Indiana. John Kasich followed suit less than 24 hours later, smoothing the way to a Trump nomination. Now, with the presidency on the line, there is a chance either Stein or Johnson (more likely the latter) will muddy up any presidential debate there may be. The time to send a message to Washington or the establishment has given way to making a serious choice between two individuals, one radical and incendiary, the other not.