The decision of the two living Republican presidents to snub the party’s 2016 White House nominee is extraordinary, yet completely predictable. It’s the culmination of an anger inside the Republican Party that gave way to an alternate history of the decades since 1980 – and especially the years after 2008.

And while it demonstrates Trump’s inability to unify the GOP, it is the best example yet of his strategy of breaking the electorate in half and hoping he wound up with the bigger piece. Losing the endorsements of George H.W. Bush and George W. Bush – as harsh an indictment as the “establishment” can offer – is no punishment at all in the eyes of many conservatives.

This was tested in real time just months ago, when the younger Bush appeared on the campaign trail for the first time in a decade. (His poll numbers cratered during the crisis-strewn final two years of his presidency, and he neither campaigned for a candidate nor appeared at the 2008 and 2012 Republican conventions.) He rallied for his brother, Jeb Bush, who started in a hole with Republican voters and became less popular as he campaigned. The result: A weak fourth-place finish in South Carolina and the end of his run for president.

The context of that loss was even worse for the Bush brand. In the hair-tearing GOP debates before the primary, Trump mocked Jeb Bush for his brother’s foreign policy record. “The World Trade Center came down during your brother’s reign,” said Trump. “Remember that.”

Conservative pundits almost universally thought Trump had blown it, insulting the Bushes in a state that had only given them election wins. “I hope the people of South Carolina will send a message to Donald Trump that we don’t like Putin, we like W,” said Sen. Lindsey O. Graham, R-S.C.

The utter failure of the Bush brand surprised some people, given that Republican voters still generally say that they like Bush. But this ignores the role both Bushes now play in conservative history – as sellouts. George H.W. Bush’s acceptance of a tax hike (forced on him by a Democratic Congress) is the Genesis story of the anti-tax movement. George W. Bush’s record in office, for all of the gains it meant for conservative, is remembered instead for the bailout, the push to legalize immigrants and No Child Left Behind.

Sen. Ted Cruz’, R-Texas, sense of the Republican base was nearly as acute as Trump’s. Since he entered electoral politics in 2010, both sought the support of the Bush family and wrote them out of his narrative. In his memoir, “A Time for Truth,” Cruz reveals that he was all set to get endorsements from the Bush family, and Karl Rove put a stop to it. More tellingly, on the trail, Cruz constantly invoked Ronald Reagan but ignored the other recent two-term Republican president.

“In the last 50 years, there is one Republican who has a group of Democrats named after him,” Cruz said during his August 2015 swing through Southern states. “If the Washington fallacy were correct – that you run to the middle to get crossover votes – then you would have Gerald Ford Democrats, or Bob Dole Democrats, or John McCain Democrats or Mitt Romney Democrats. They don’t exist.”

Cruz skipped over two people – the Bushes, the last Republicans to win presidential elections. Cruz, who worked for the younger Bush’s 2000 campaign, was well aware that he ran as a center-right pragmatist, who favored national education standards and immigration reform. But saying so contradicts the theory that only true conservatives win the presidency. At one Cruz campaign stop in Nevada, Rep. Raul Labrador, R-Idaho, told an even more tailored version of the history.

“We’ve had three Republican nominees in the last few years,” he said. “One of them was Bob Dole. If you think about it, he was the ‘electable’ one. Then we had John McCain. He was supposed to be the ‘electable’ one. Then, there was Mitt Romney.”

Labrador skipped right over George W. Bush, who won two national elections and swung the Supreme Court to the right. He did so in service of Cruz, the candidate who ran second in the primary, defeated only by the one who personally insulted the Bushes. All of that may give Trump confidence that he is being snubbed by exactly the right sort of people.

(c) 2016, The Washington Post · David Weigel