Jeb Bush suspended his presidential campaign Saturday, ending a quest for the White House that started with a war chest of $100 million, a famous name, and a promise of political civility, but ended with a humbling recognition: In 2016, none of it mattered.

No single candidacy this year fell so monumentally short of its original expectations. It began with an aura of inevitability that masked deep problems, from Bush himself, a clunky candidate in a field of gifted performers, to the rightward drift of the Republican Party since Bush’s time as a consensus conservative in Florida.

Bush’s campaign had rested on a set of assumptions that, one by one, turned out to be flatly incorrect: that the Republican primaries would turn on a record of accomplishment in government; that Bush’s cerebral and reserved style would be an asset; and that a country wary of dynasties would evaluate this member of the Bush family on his own merits.

“We’ve had enough Bushes,’’ his mother, Barbara Bush, observed, prophetically, before her son had announced his candidacy last summer.

In what turned out to be the year of the unconventional outsider, Bush conducted his campaign as the conventional insider.

Last summer, as Donald Trump prepared to declare his candidacy with an incendiary and improvised speech in New York City about the criminal records of immigrants from Mexico, Bush was in Eastern Europe, meeting with heads of state and delivering carefully calibrated remarks about the future of US diplomacy.

Bush, 63, the former two-term governor of Florida, failed to inspire Republican primary voters whose mood and needs had changed dramatically since he left government in 2007.

Now, they are eager for a candidate as angry and restless as they are. Standing on debate stages next to the likes of Trump and Senator Ted Cruz of Texas, Bush never seemed to convincingly play the fighter.

After promising to conduct a “joyful’’ campaign, Bush instead found himself locked in an ugly and dejected slog, under gleeful attack from his rivals and heightened scrutiny from the political world he had thought was rooting for him.

In a painful twist of the knife, Bush was overtaken by his former political protégé, Senator Marco Rubio, whose career he had diligently nurtured in Florida.

But by far his biggest liability, aides and advisers concede, was a pedigree he could do nothing to erase or dilute: He was a Bush, through and through, at a time when voters despised the political and economic establishment that his family name embodies.

Maria Losito, 65, and her husband, Frank, 65, both retirees in Palm City, Fla., said they couldn’t quite bring themselves to support Bush. “The father was president; the brother was president,’’ Maria Losito said. “How do I trust him that he’s going to change things that his father and brother didn’t?’’

But Frank Losito said he felt for Bush. “It’s sad in [a] way,’’ he said, “because he’s pouring all this money in, and he’s not getting anywhere.’’

The long, slow tumble within the Republican campaign was a nightmarish scenario for Bush, who had remained highly skeptical about whether to enter the race in the first place.

A successful business executive in Florida, he had turned his family name and time as governor into a lucrative network of companies and consulting contracts, amassing a net worth in the tens of millions of dollars. His wife, Columba, who never relished politics, seemed ambivalent, and his immediate family was not eager for the scrutiny that a presidential run would invite.

But as 2016 approached, old friends and a powerful network of Bush donors pleaded with him to become a candidate, assuring him they would raise the required money. With astonishing speed and alacrity, they did just that — more than $100 million for the super PAC supporting him, contributing to the campaign’s air of confidence and strength.

But he stumbled out of the gate — struggling to handle both his famous last name and the legacy of his brother, President George W. Bush, who led the nation into a deeply unpopular war in Iraq to pursue weapons of mass destruction that never materialized.

Bush promised to campaign as his “own man,’’ first trying to distance himself from his family, and later extolling his mother, father, and brother at every turn. When he rolled out a list of foreign policy advisers, they largely hailed from previous Bush administrations.

In one of his campaign’s lowest moments, he repeatedly bungled an early question about whether he would have authorized the 2003 invasion of Iraq, as his brother had, given the intelligence known today. What seemed like the simple and inevitable answer did not arrive for days, after multiple, widely ridiculed attempts.

He was gaffe-prone and awkward on the campaign trail, interrupting his own sentences on stage, and appearing uncomfortable during debates.

In this crowded Republican field, compelling debate performances were a necessity. But Bush seemed at his weakest during the prime time rumpuses, a problem that became indelible on Oct. 28 in Colorado.

For that contest, Bush had rehearsed a direct confrontation with Rubio. But Rubio was prepared and turned the attack back on Bush, leaving Bush devastated.

Bush improved somewhat as a debater, but he never seemed to dominate the encounters.

The uneven performances earned Bush a memorable moniker from Trump — “low energy,’’ which the real estate developer repeated at every turn. But in what many of Bush’s supporters now say was a strategic error, his campaign did not immediately push back against the schoolyard taunt.