It's a once every four years political prom.
This time around, the red, white and blue draped elephants of the Republican National Convention is in Cleveland.
And, some of the most familiar GOP faces are sitting on the sidelines, including the last two Republican nominees -- Mitt Romney and John McCain -- the last two Republican presidents -- George W. Bush and his father George H.W. Bush -- as well as former presidential hopeful, Jeb Bush, according to reports from CNN.
The former Florida governor, who openly sparred with Trump during several of the presidential primary debates, has continued his opposition of the expected Republican nominee Donald J. Trump.
"I do not believe Donald Trump reflects the principles or inclusive legacy of the Republican Party," Jeb Bush wrote in an opinion piece published Friday by the Washington Post.
Skipping the party's nominating convention is something that's even "disappointed" 92-year-old Purple Heart war veteran and former Kansas senator Bob Dole, according to a recent report by The Hill. Dole, the only Republican presidential nominee not named Bush between 1988 and 2004, is at the convention.
RELATED: Breitbart report... Ten Top Republicans Sitting out the RNC Convention
Others from the primary field, however, have jumped behind the Trump-Pence ticket.
At least one, Ben Carson, will have a front-and-center position as a primetime, headline speaker Tuesday night.
Pediatric neurosurgeon Dr. Ben Carson was one of the first candidates to endorse the campaign of Donald J. Trump after dropping out of the race this spring.
Here's a look at who's in Cleveland and who's not from that crowd of 16 other primary candidates not named Donald J. Trump.
Although he's not officially endorsed Trump, GOP runner-up Ted Cruz will speak at the convention on Wednesday. He's expected to thank his supporters, according to the Los Angeles Times.
Like Cruz, Marco Rubio has yet to publicly endorse Trump, but will address the convention on Wednesday, according to reports in the Dallas Morning News. Reports only last week from the Associated Press suggested Rubio would skip the convention.
Former Texas Gov. Rick Perry is expected to address the convention tonight.
Former New Jersey Gov. Chris Christie wasn't happy about not being picked as Trump's running-mate, according to the Washington Post, but is expected to speak at the convention in Cleveland Tuesday.
Wisconsin Gov. Scott Walker is expected to urge support for Trump when he speaks at the convention on Wednesday, the Wisconsin State Journal reported.
Former Arkansas Gov. Mike Huckabee has been outspoken against those who are sitting out the convention. According to a report in the Dallas Morning News, Huckabee said they were acting with "petulance" and "dishonor." Politico reported that Huckabee said Trump opponents shouldn't be allowed to speak at the convention.
Absentees at #RNCinCLE:
The Republican governor of the state hosting the convention isn't endorsing Trump renewing acrimony between the two that existed during the primary campaign, according to a New York Times report. Although some reports state he's in Cleveland, is forecast to stay away from the convention platform.
Sen. Rand Paul, who has previously endorsed Trump, will not attend the convention in Cleveland, according to Fox News reports.
Former Louisiana Gov. Bobby Jindal announced he's voting for Trump in the Wall Street Journal, but wasn't expected to attend the convention, according to an NDTV report.
In a rare move during the primary process, Fiorina was chosen as running-mate to Ted Cruz while he still trailed Trump. Fiorina has not yet reportedly jumped behind Trump's expected nomination, and isn't expected to be in Cleveland.
South Carolina Sen. Lindsey Graham has been on-again, off-again on Trump's nomination to lead the GOP into November. He's sitting out Cleveland, however, according to an Associated Press report last week.
A New York Post report stated former New York Gov. George Pataki declined a chance to be a Trump delegate, however, he "was expected to back Trump."
Unclear whether they're in Cleveland:
The former Pennsylvania senator is endorsing Donald J. Trump, according to Philly.com, but it remained unclear whether he was in Cleveland for the convention.
This former Virginia governor is behind Trump, but won't be a delegate at the convention in Cleveland, the Political Insider reported.