Former 2016 presidential candidate Jeb Bush announced late Friday he will not support Donald Trump for president, joining South Carolina Sen. Lindsey Graham and other GOP figures giving the presumptive nominee the cold shoulder.

Trump, meanwhile, said he’s getting endorsements “left and right” and brushed off the comments of party figures and ex-candidates speaking out against his bid.

Of Graham, he said in a statement: "I fully understand why Lindsey Graham cannot support me. If I got beaten as badly as I beat him, and all the other candidates he endorsed, I would not be able to give my support either.”

Bush announced his formal opposition to Trump on Facebook. The former Florida governor congratulated the billionaire businessman for wrapping up the nomination but went on to say: “Donald Trump has not demonstrated that temperament or strength of character” required to lead the nation.

“He has not displayed a respect for the Constitution. And, he is not a consistent conservative. These are all reasons why I cannot support his candidacy,” Bush said.

He also said Democratic front-runner Hillary Clinton is an “untrustworthy liberal politician” and so, “In November, I will not vote for Donald Trump or Hillary Clinton, but I will support principled conservatives at the state and federal levels.” 

Bush, early in the Republican primary race last year, had been considered the candidate to beat only to get hammered by Trump in the debates and, later, in the primaries themselves. He, along with former candidate Graham, eventually dropped out. 

Graham voiced similar sentiments in his statement, saying he will not support Clinton or Trump. 

“I absolutely will not support Hillary Clinton for President. … I also cannot in good conscience support Donald Trump because I do not believe he is a reliable Republican conservative nor has he displayed the judgment and temperament to serve as Commander in Chief,” Graham said. 

He added he does not plan to attend the Republican convention in July.

Other former primary rivals have gotten behind Trump, including retired neurosurgeon Ben Carson, now involved in the running mate selection process, and New Jersey Gov. Chris Christie.

Former Texas Gov. Rick Perry, a former critic of Trump, also now says he'd be willing to work in a Trump administration, even as vice president.

Trump has made no such public overtures to the longtime Texas governor, who acknowledged he hasn't spoken to Trump in months.

"If Donald Trump says, `Perry, let's talk about you helping in this role,' I'm open to it," Perry said Friday.

Trump tweeted "Thank you Rick!" after Perry's endorsement.

Trump also has been sparring from afar with House Speaker Paul Ryan, who on Thursday said he’s not ready at this point to support Trump. However, the two plan to meet next week.

Also supporting Trump is former Vice President Dick Cheney, who told CNN that he has always supported the GOP nominee, as well as former Kansas senator and 1996 Republican presidential nominee Bob Dole.

The Associated Press contributed to this report.