“Mr. Bush left many voters on the right angry, resentful and suspicious — of war, of policy, of ideology, of the very idea of political solutions and leadership”

There is always some space between a party’s voters and its leaders, some difference between what the average supporter wants and what the elected representatives are willing to do. But by excusing Mr. Bush’s errors, Republicans radically expanded the trust deficit, creating a yawning gap between the party’s base and its elites, one that has persisted, and grown, in the years since.

In many ways, the party’s hangups stem from its unwillingness to fully reckon with the Bush legacy.

Mr. Bush left many voters on the right angry, resentful and suspicious — of war, of policy, of ideology, of the very idea of political solutions and leadership.

The focal point for much of the post-Bush right’s anger and resentment was the Tea Party, a decentralized movement that variously mixed genuine desire for limited government with white resentment and flare-ups of outright paranoia. It attracted hucksters and manipulators, in the media and in the activist sphere, and embraced a cast of unconventional and unqualified candidates.

Republican Party elites were only too happy to exploit this inchoate energy as long as it was useful. This is how John McCain ended up selecting an untested firebrand like Sarah Palin as his presidential running mate and how Mitt Romney campaigned with sideshow characters like Kid Rock and, well, eventually Donald Trump.

The partisan push for the Affordable Care Act under President Barack Obama further amplified these frustrations, which helped Republicans take over the House in 2010.

The defeats of both Mr. McCain and Mr. Romney left the party leaderless, and Mr. Bush’s shredded reputation meant it could not follow the course he had laid out. So the party became defined by what was left: its resentments and suspicions, its antagonisms and obsessions, its anger and its differences. It retreated into tribalism and anti-intellectualism. Eventually, the sideshow became the main event.

Mr. Trump, of course, is the biggest sideshow of them all. He exploited the gap between the base and the elites, embodying the dysfunction and disarray that already existed.

Like all presidents, he serves an organizing function for his party, orienting it around broad goals. But Mr. Trump’s goals have more to do with Twitter feuds and personal aggrandizement than any particular policies. Under Mr. Trump, the party’s chief internal debate is not so much about which governing vision to pursue but whether there should be one at all.

Peter Suderman, “The Republican Party Is a Mess”, The New York Times (14 October 2017), A19.