WASHINGTON — The epic sibling drama of the Republican Party is finally coming to a climax.

For many years, George and Barbara Bush assumed that their second son, Jeb, would be a winner in politics, while W., their eldest, would be a loser.

Jeb was the prince of the dynasty, destined to be king. (Poppy Bush would only call their dynasty “the d word,” wrinkling his nose in a vain attempt to seem like a Greenwich populist.)The raffish, Roman candle, W., on the other hand, was discouraged by his mother from running for governor of Texas when his father was in the White House. Bar also did not want W. to run for that office in 1993 at the same time that Jeb was running for governor of Florida, for fear that W. would divert too much money from the Bush Rolodex of donors and turn the contest into “a People magazine story,” as Jeb resignedly called it back when he told me he couldn’t “control” his older brother.

Democrats began mocking them during their twin races as “Tweedledee and Tweedledum,” especially after W. began stealing Jeb’s best campaign lines. Yet when I covered the fraternal gubernatorial bids in the South, it was quickly apparent that W. had a crackle that Jeb did not have, not to mention a crack consultant: Karl Rove. W. was driven by a zeal to prove his parents wrong, one of the most powerful impulses on earth.

Jeb, the Good Son, seemed more phlegmatic, bogged down in wonky discourse about “visioning,” “prioritizing,” “empowering” and “sharing a good exchange of ideas.”

Jeb lost his race and W. won his, starting the reversal that would lead to W. becoming the black-sheep king, once Jeb had helped secure Florida for him. Now Jeb has to figure out if W. has fouled the waters forever, or if Americans, lulled by the ex-president’s winsome paintings, have grown less disgusted by his disastrous wars, misadventures in torture and economic belly flop. Jeb’s father desperately wants him to run and his mother now says it would be O.K., despite her reservations about two families trading Air Force One back and forth.

As Hillary Clinton prepares to restore her dynasty, Jeb Bush is dropping a handkerchief about restoring his.

He has campaigned for Republicans around the country and influential donors in the G.O.P. have started a draft-Jeb movement. He was the speaker at a V.I.P. dinner in Las Vegas with Sheldon Adelson. He has reached out to Southern evangelical leaders. And he had a star turn at the 25th anniversary celebration of his father’s presidency over the weekend at the George H.W. Bush library in College Station, Tex.

But is Jeb’s race over before it begins? He would be running, after all, to lead a party he seems to disdain, a party that has become so fragmented and pulled to the right that it would rather lose the election than be led by someone as moderate as Jeb Bush. Even W. is considered a liberal in today’s fire-breathing G.O.P.

“I do think we’ve lost our way,” Jeb said in an interview on stage with a Fox News reporter, urging Republicans to move out of Crazy Town: “We need to elect candidates that have a vision that is bigger and broader, and candidates that are organized around winning the election, not making a point.”

Sounding nostalgic for a world before Dick Cheney, Sarah Palin and Ted Cruz, the 61-year-old said he would only run if he could bring a “hopeful” message and campaign “joyfully,” avoiding “the vortex of the mud fight.”

Then he stumbled into the vortex by repeating his support for Common Core education standards and by trying to inject some compassion into the immigration issue, which sends older, white Tea Partiers into frenzies of fanaticism.

“Yes, they broke the law, but it’s not a felony,” he said of illegal immigrants sneaking into the country to provide for their families. “It’s an act of love.” (Jeb has been married to the Mexican-born Columba for 40 years.)Karl Rove and Bill Kristol mused that Jeb’s “Bulworth” moment, as Politico dubbed it, may show he’s been out of the mix for too long. Conservative columnist Byron York suggested that the “mud-fight-averse” Jeb “just doesn’t seem like a politician in top fighting shape.” Michelle Malkin tweeted: “He’s pro-amnesty, pro-Common Core, pro-Big Business & he wants to be president. #CancelJebBush.” Marco Rubio said he would not step aside for his mentor in a presidential race. And Stephen Colbert eulogized, “He will be missed.”

Some of those close to Jeb say he’s serious about running and bringing back a civil tone to Republican politics. Others say he needs to act as though he’s running to keep his speaking fees high and options open. Rush Limbaugh thinks Jeb’s “act of love” comment was a gambit to tick off the Tea Party and “get the conservative backlash to him out of the way.”

Jeb thinks Republicans have lost their way. He may soon learn that a lot of conservatives think they have found their way — and it’s not the joyful, loving, government-can-be-a-force-for-good way. It’s the mean, cruel, gut-the-government way.

When this crowd thinks of A Thousand Points of Light, they’re thinking of torches as they march toward the Capitol.