I owe my girlfriend a steak dinner.

A while ago, before Donald Trump won five East Coast primaries by huge margins, before he followed that up by winning Indiana, which he did Tuesday night, before he beefed up his campaign staff, before he built up a commanding delegate lead, before GOP “leaders” began to make a repulsive peace with him, I bet my girlfriend a steak dinner that Trump would not be the Republican presidential nominee. Whoops.

Trump has humiliated those of us who doubted him. Or maybe that is not quite right. Trump has humiliated those of us who gave the Republican Party the benefit of the doubt. Surely the competent hands running against him would make Trump appear as out-of-his-depth as he is? Even after these leaders proved uninspiring, surely there would be enough voters left in the party who recognize that Trump is about as transparent a con man as the “Simpsons” monorail salesman? In fact, the Republican Party is proving that it is filled with Homers. At this point, Trump leads — bigly, as he would say — in national polls of GOP voters, with nearly 50 percent of Republicans behind him. His approval numbers among Republicans are also reviving. He is right on course to getting the 1,237 delegates he needs to take the nomination on the first ballot. He is Republican voters’ choice.

After losing the Republican primary in Indiana, Sen. Ted Cruz (R-Tex.) said he was "leaving it all on the field." GOP front-runner Donald Trump commended Cruz, calling him "a tough, smart competitor" - a complete reversal from the insults he had been using earlier in the day. (Sarah Parnass/The Washington Post)

In retrospect, perhaps Trump’s triumph was more predictable. After all, this is a party that rejected the closest they had to thoughtful candidates early on in the primary. A party that has tolerated and benefited from outrageously insulting myths about President Obama, his heritage and his agenda. A party that has repeatedly and recklessly abused the statutory debt limit and the budget process. A party that sneers at those concerned about climate change. A party that covers up its deficiencies by assaulting the legitimacy of the mainstream press. A party that, as a partial result, often seems incapable of sorting exaggerations and lies about public policy — “Obamacare has death panels!”; “climate regulations would destroy the economy” — from facts. A party whose leaders have made outrageous and unkeepable promises to increasingly frustrated voters. A party that, when given the choice between staging a grand emotional outburst and governing, has repeatedly chosen to stage a grand emotional outburst.

Trump may have more humiliations in store for us. Surely nominating an embarrassingly unprepared demagogue will result in total electoral disaster for the GOP? Surely Trump will lose not just independents, but also conscientious Republicans who recognize what a threat he is? Surely many of these Republicans will vote for Hillary Clinton instead — or at least not vote at all — in November? Surely their partisanship and anti-Clinton animus will not blind them to Trump’s obvious unsuitability for the job? Surely they will realize that they probably cannot win with a Trump ticket in a general election, but they can at least save themselves from moral oblivion? Surely the electoral map will be drastically different from that of the last several elections? Maybe, but I’m not betting a steak dinner on it.