It was more or less unthinkable to write those words at the beginning of the year, but here we are.
Stopping Trump is now the responsibility of Hillary Clinton, who will almost certainly be the Democratic nominee for President. She will have the last, best opportunity to take Trump down. Along with much of the rest of the world, I am hoping she does not fail.
The odds of a Democratic win are good. The geography of the electoral college favours them. Trump's odiousness is such, to voters in general and minorities in particular, that formerly solid Republican states like Texas and Arizona may be put into play. But it would be foolish for the Democrats to be complacent.
Make no mistake: Trump could win. He is riding a wave of anti-establishment anger, and Clinton is the quintessential establishment candidate. She is loved by few and disliked by many. Some of this dislike is manufactured, by what Clinton herself once called the "vast right-wing conspiracy". It may be unfair, but needless to say, presidential politics is not a fair arena.
Even if Trump loses, a great deal of damage has already been done. The nomination for President is a serious position. It brings enormous visibility, vast amounts of media time, and a strong chance of becoming leader of the world's only superpower. As a bully pulpit, it is perhaps second only to the Presidency itself.
For the next six months, this crucial position will be held by Donald Trump. He will have a highly visible platform from which to articulate his brand of hatred, bigotry and ignorance. If Trump loses by anything less than a crushing landslide, his politics will live on.
How did it come to this? How did the party of Abraham Lincoln, Theodore Roosevelt, and Dwight Eisenhower end up nominating this hateful buffoon?
The Base Unchained
The rot has been growing for some time. Maybe it started with the cheerful ignorance of Ronald Reagan, and the swaggering cowboy act of George W Bush. It metastasized with the raging stupidity of Sarah Palin, and then her imitators in the Tea Party, including a first-term Senator named Ted Cruz.
For many years, the Republican establishment pandered to the worst instincts of the electorate. They encouraged people to get mad and blame the immigrants, the blacks, the gays, the atheists, the elites with their fancy book-learning, for everything that afflicts them. Once in power, for the most part they ignored the real economic concerns of the voters who were taken in. They proceeded to deregulate business and cut taxes for the rich, which exacerbated the economic woes of struggling workers, who were encouraged to heap yet more blame on the usual targets.
It worked pretty well, until it didn't. The establishment thought they had tamed the slavering rage monster of the base. Around election time, they gave it chunks of red meat, let it out to roar and stalk the landscape for a while, then chained it back up in the basement. When the monster broke loose, the mainstream candidates were helpless, because they could not speak its language of hate and fury.
One after another served as standard-bearer for business as usual: Scott Walker, Jeb Bush, Marco Rubio, John Kasich. None came close to commanding a majority of the anti-Trump vote. It didn't help that for the most part, they were terrible campaigners; but in this election, even a highly gifted politician would have struggled to turn back the wave of anger at the status quo.
Instead, Trump's only serious rival was the repulsive Ted Cruz, who built his career on being a far-right rebel against his own party. For primary voters, the fact that Cruz is despised by the party establishment was a point in his favour. Unfortunately for Cruz, he is also despised by nearly everyone else who takes a close look at him.
Now Cruz and Kasich have given up, and Trump is the last man standing.
The Republican Party could still deny Trump the nomination. It would be within the letter of the party rules to tear up the existing rulebook, draft new rules to exclude Trump, and offer the nomination to someone else. But I doubt they have the nerve to attempt this.
Another, slightly more plausible option is a third-party candidacy. Some Republicans are openly calling for one of their number to run against both Trump and Clinton as an independent.
The timing of Cruz' withdrawal from the race is interesting. If he had waited until the party convention in mid-July, it would have been too late to organise a third-party candidacy. Deadlines to register as a candidate vary by state, but many will fall soon. The first is Texas, where a prospective candidate must gather signatures by a deadline... three days from now. It seems unlikely, although we shall see what the weekend brings.
The next registration deadlines are in late May, so if he declared at once, an independent could still register in the majority of states. In others such as Texas, the candidate could try to persuade a minor party which is already on the ballot to make him its nominee, or campaign as a write-in candidate.
An interesting thing is that under the US Constitution, if no candidate receives an outright majority in the Electoral College, the House of Representatives chooses the President. As long as the election is settled by the House, a Republican in good standing may have a strong chance. Being a spoiler who wins a handful of states could prove to be enough.
Again, I doubt many Republicans have the stomach to provoke open conflict in their party like this. It is a pity, because against someone as despicable as Trump, relentless opposition seems like the best option. The modern GOP is well known for its obstinate refusal to compromise with Obama; it's too bad they can't turn some of that against a more deserving target.
It seems the party establishment wishes to hide, and wait for this election to resolve itself without them. Prominent figures such as former Presidents George HW and George W Bush are refusing to endorse Trump; but out of residual party loyalty and dislike of Hillary Clinton, they cannot bring themselves to campaign against him openly.
Meanwhile Trump slouches onwards, his path unobstructed now, towards the party conventions, the campaign, the debates, and the election itself.
The American electorate has come in for a lot of criticism over the years. Some of it is deserved, but in the end, they usually do a good job of choosing Presidents. American values of fairness, kindness and tolerance are strong; I hope strong enough to reject Trump's message of incoherent hate.