Part of President Barack Obama's endorsement and support of Democratic nominee Hillary Clinton means the commander in chief hitting the campaign trail. And part of stumping for Clinton has meant weighing in on Donald Trump. 

"Stop whining and go try to make his case," was Obama's suggestion for Trump when asked about the GOP nominee's warnings of voter fraud during a press conference in the White House Rose Garden on Tuesday with Italian Prime Minster Matteo Renzi.

"The notion that somehow if Mr. Trump loses Florida, it is because of those people that you have to watch out for — that is both irresponsible and, by the way, doesn’t really show the kind of leadership and toughness that you want out of a president."

The Rose Garden comments were only the latest criticism Obama has had for Trump. In most election years, the sitting President publicly supports the nominee from his or her own party, but Obama has gone a step further, suggesting that Trump is an unprecedented and unqualified candidate who is unfit to serve in the White House. 

President Obama President Barack Obama has not shied away from criticizing GOP nominee Donald Trump over the course of the 2016 election cycle. Photo: Getty Images

Here are five other times Obama has gone after Trump.

Trump On Women

Obama spoke at a Clinton campaign event earlier this month and responded to the mounting allegations of sexual abuse against Trump and the release of audio from 2005 revealing Trump making lewd comments about women and speaking casually about sexual assault. Obama said that Trump's history of treatment of women and the divisive rhetoric the GOP nominee has used on the campaign trail made him unfit for office. 

"Are we really going to risk giving Donald Trump the power to roll back all the progress we've made?" Obama asked. "I don't need to repeat [Trump's disparaging comments]. There are children in the room. Demeaning, degrading women, but also minorities, immigrants, people of other faiths, mocking the disabled ... He puffs himself up by putting other people down."

Trump Is Unfit

Obama's criticism of Trump reached a tipping point in August when Obama declared that Trump was "unfit to serve" as president. Speaking at a joint press conference with Singapore Prime Minister Lee Hsien Loong, Obama called Trump "woefully unprepared" for the job. 

"There have been Republican [presidential candidates] with whom I disagreed with, but I didn't have a doubt that they could function as president," Obama said. "I think what [GOP leaders] have to ask themselves is, if you are repeatedly having to say, in very strong terms, that what he has said is unacceptable, why are you still endorsing him? What does this say about your party, that this is your standard-bearer?"

The Democratic National Convention

Obama spoke at the Democratic National Convention in July and attacked Trump's appeal to working-class Americans. Mockingly referring to the candidate as "The Donald," Obama questioned why voters expected a wealthy, self-interested businessman to effectively be the hero of the working class. 

"And then there’s Donald Trump. 'The Donald' is not really a 'plans guy.' He's not really a 'facts guy,' either. He calls himself a 'business guy,' which is true, but I have to say, I know plenty of businessmen and women who’ve achieved success without leaving a trail of lawsuits, and unpaid workers, and people feeling like they got cheated," Obama said. "Does anyone really believe that a guy who’s spent his 70 years on this Earth showing no regard for working people is suddenly going to be your champion?"

Trump's Border Wall

One of the hallmarks of Trump's campaign has been his promise to build a wall on the U.S.-Mexico border and make Mexico pay for it. Making a foreign country fund a controversial border fence would certainly have its challenges and Obama weighed in on the proposal in April, dismissing the idea as impractical. 

"This is just one more example of something that is not thought through and is primarily put forward for political consumption," Obama said. "I've tried to emphasize throughout [that] we've got serious problems here. We've got big issues around the world. People expect the president of the United States and the elected officials in this country to treat these problems seriously, to put forward policies that have been examined, analyzed, are effective, where unintended consequences are taken into account."

White House Correspondents Dinner 

Trump attended the White House Correspondents Dinner in 2011 amid his personal campaign to convince Obama to release his long-form birth certificate and prove that he was, in fact, born in the U.S. When it was Obama's turn to speak at the comedy-filled event, he poked fun at Trump and the conspiracy theory the real estate mogul had helped popularize. Obama even joked about Trump's presidential rumors, which were then just rumors and fodder for jokes. If only he knew. 

"No one is happier, no one is prouder to put this birth certificate matter to rest than the Donald. And that’s because he can finally get back to focusing on the issues that matter, like, did we fake the moon landing? What really happened in Roswell? And where are Biggie and Tupac?" Obama joked. "Say what you will about Mr. Trump, he certainly would bring some change to the White House.  Let’s see what we’ve got up there."