When Democrats gather for their national convention in Philadelphia, the list of speakers praising Hillary Clinton’s presidential candidacy is expected to feature the president, the vice president, the first lady, a former president and a galaxy of well-known political luminaries.

But when the Republican convention opens next week in Cleveland, presumptive nominee Donald Trump will showcase an assortment of family members, defeated primary opponents and politicians whose names barely register with the general public. Many of the GOP’s past, current and future leaders are staying away from the spotlights at the Quicken Loans Arena.

The star-power disparity between the conventions speaks volumes about the state of the two parties — one is united and marching together toward what it hopes will be its fifth win of the past seven presidential elections, while the other remains divided and still not fully accepting its new standard bearer.

“Republicans have always had a terrible star-power deficit — the Democrats have the latest hip-hop or pop act and we’ve got Lee Greenwood and the Oak Ridge Boys — but now it’s going to be even more pronounced,” said Rick Wilson, a Republican strategist who is not supporting Trump.

Looking ahead to Philadelphia, Wilson said of the Democrats, “Bill Clinton, Hillary Clinton, Barack Obama, Michelle Obama, Elizabeth Warren — they’re all going to be out there swinging for the fences. But the Republicans, it’ll be like a hostage video of people forced on stage.”

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Warren, a senator from Massachusetts who is considered a finalist to be Clinton’s running mate, is expected to give a major address, as are two other vice presidential prospects, Sens. Timothy M. Kaine (Va.) and Cory Booker (N.J.). Other expected speakers include Sen. Bernie Sanders (Vt.), who on Tuesday ended his presidential campaign and endorsed Clinton after weeks of holding out.

On the Republican side, House Speaker Paul D. Ryan (Wis.) looks to be the highest-profile party leader. He will officially chair the convention and plans to give a speech in addition to his ceremonial duties. His remarks are expected to center on his conservative House agenda, “A Better Way,” and a call for Republican unity.

The highlight performances next week could come from members of Trump’s family. His wife, Melania Trump, rarely speaks in public, but has been preparing remarks, and his three adult children, especially daughter Ivanka Trump, could open a window into their father’s character. Four years ago, Ann Romney delivered one of the most memorable speeches of the GOP convention in Tampa when she spoke of the love story with her husband, Mitt.

Still, the absences in Cleveland will be notable.

The past two Republican nominees, Mitt Romney and John McCain? Not coming.

The party’s only two living past presidents, George H.W. Bush and George W. Bush? They’re skipping, too, as is Jeb Bush, a former Florida governor who lost to Trump in the early primaries.

A whole host of influential Republicans have decided not to attend July's Republican National Convention in Cleveland. (Peter Stevenson/The Washington Post)

What about the diverse constellation of stars oft-promoted by the GOP in the six years since they swept into office, including South Carolina Gov. Nikki Haley, New Mexico Gov. Susana Martinez and Sen. Marco Rubio (Fla.)? You won’t see them speaking in Cleveland, either.

“The fact that the party elders aren’t willing to come make his case says a lot about the state of the Republican Party,” said Bill Burton, a Democratic strategist. “To the extent that Trump is having trouble getting speakers who can tell his story and tell the story he wants to tell about Hillary Clinton — it’s a larger lift.”

Russell Schriefer, a longtime Republican strategist who helped run the party’s 2012 convention, said, “You don’t hear of any major Democratic figures saying they’re staying home because Hillary Clinton’s the nominee. That is the case with Trump.”

But Schriefer said the absence of more established luminaries presents “an opportunity for Republicans for stars to be born at the convention.” He noted that Barack Obama’s breakout turn came at the 2004 Democratic National Convention in Boston, when he was an Illinois state senator.

For months now, Trump has promised that his convention would be unlike any other — a dazzling, spectacular affair that soars above traditional political theater. In an April interview with The Washington Post, he said the Tampa gathering four years ago was “the single most boring convention I’ve ever seen.” He vowed to bring a “showbiz” quality to Cleveland.

“It’s very important to put some showbiz into a convention, otherwise people are going to fall asleep,” he said.

Trump has teased various plans for Cleveland, such as a “winner’s night” starring sports heroes and cultural icons of decades past. But he and his campaign team have been tight-lipped about a lineup.

A list of speakers still had not been released as of Wednesday afternoon — a full week since Trump promised to do so — suggesting a last-minute scramble to book speakers. Republican operatives have complained privately this week that likely speakers have not been given final word on when they will address the delegates or what themes the Trump team would like them to discuss in their remarks. Such late uncertainty is unusual, as political conventions tend to be tightly scripted and highly choreographed.

Members of the Republican National Committee, which puts on the convention and is meeting in Cleveland this week, said they have been kept in the dark about the convention program.

“Donald Trump’s run an unconventional campaign from the get-go, and he said right from the outset he wanted an unconventional program with not the usual speakers,” said Steve Duprey, an RNC member from New Hampshire. “Frankly, it might stir up more interest than parading out past luminaries of a party. Maybe the Trump way will work.”

The celebrities planning to be in Cleveland next week include Caitlyn Jenner, a former Olympian, reality television star and transgender advocate, and musical acts Kid Rock, Lynyrd Skynyrd, Rascal Flatts and Big & Rich.

The Democrats traditionally draw more A-list celebrities, and this year will be no different. Among the actors and recording artists planning to attend are Lady Gaga, Snoop Dogg, Fergie, Lenny Kravitz, Idina Menzel and Bryan Cranston.

In Cleveland, Republicans who have been supportive of Trump will get top billing. They include Sen. Joni Ernst (Iowa), who burst onto the scene in 2014 with a playful campaign ad vowing to apply her hog-castration skills in Washington to “make ’em squeal.” Trump eyed her as a possible vice-presidential running mate, and they met on July 4, although she later took herself out of consideration.

Sen. Tom Cotton (Ark.), who also joined the Senate last year, plans to speak as well. Cotton is among a handful of young Republicans considered likely future presidential candidates. Another is Sen. Ben Sasse (Neb.), although he is a vocal Trump critic and will not be in Cleveland. Instead, Sasse plans to “take his kids to watch some dumpster fires across the state,” his spokesman provocatively told reporters.

At least two of Trump’s primary opponents — Sen. Ted Cruz (Tex.) and Wisconsin Gov. Scott Walker — are planning to address delegates in Cleveland.

Cruz and Walker are trying to rebuild their profiles after being wounded in the nomination battle, looking to another run in four years. Yet neither has fully endorsed Trump, and it is unclear whether either plans to vouch for him.

Former Arkansas governor Mike Huckabee, another 2016 contender, also plans to speak.

Among the former Trump rivals not planning to address the convention is John Kasich, who as governor of Ohio is something of a host for the week-long gathering. He has said that he plans to be in Cleveland next week but that he does not intend to step foot in the convention hall or speak on Trump’s behalf.

Trump’s vice-presidential running mate will give a formal address, although the runners-up also could have a turn on stage. A trio of finalists — Indiana Gov. Mike Pence, New Jersey Gov. Chris Christie and former House speaker Newt Gingrich (Ga.) — have been top supporters of Trump, as have Sens. Jeff Sessions (Ala.) and Bob Corker (Tenn.).

Some Republican strategists worry, however, that the Cleveland convention will not showcase the full breadth of the GOP’s diversity, both racially and generationally. In addition to Rubio and Martinez, two rising stars, Reps. Mia Love (Utah) and Elise Stefanik (N.Y.), are staying home.

“On Earth 2,” Wilson said, “you’d be showing the Republican Party isn’t this stupid white boys’ club. But Donald Trump has rejected everybody who’s not in the stupid white boys’ club. At this point, we might as well have a giant cross burning out front.”

An antidote to that picture of the party are two Republicans from South Carolina: Haley, the state’s first Indian American governor, and Sen. Tim Scott, its first black senator. Both will be in Cleveland for the festivities — but neither plans to take the stage.