Tempers flared and political fault-lines were inflamed as aides to Donald Trump and Hillary Clinton gathered for their first meeting since election day.

Every four years since 1972, top presidential campaign aides have met for a polite discussion of the fierce battle they just waged.

Not so this year.

After an election that left the political world spiralling, this year's gathering at Harvard University's Institute of Politics felt an awful lot like group therapy — or a knife fight. Stony-faced campaign aides heckled pollsters, jeered top media executives and shouted charges of racism, sexism and fear-mongering.

"Let's be honest, don't act as if you have some popular mandate for your message," said Hillary Clinton's chief strategist Joel Benenson, citing Clinton's more than two million-vote lead in the popular vote.

"Hey guys, we won," Kellyanne Conway, Donald Trump's former campaign manager, shot back. She later added: "Hashtag: he's your president. How about that?"

Trump's aides defended his controversial statements, including his recent comments about criminalizing flag-burning, a Muslim travel ban and his racial comments about a federal judge overseeing class-action lawsuits against Trump University.

"I think the American people agree with him that burning the flag is wrong," said former Trump campaign manager Corey Lewandowski, who was fired in June. "I don't care what the Supreme Court has said."

Clinton's team said they didn't regret their responses to Trump's racist and sexist remarks, saying they were some of their proudest moments in the race.

"I would rather lose than win the way you guys did," said Clinton's communication director Jennifer Palmieri, her voice shaking.

"Do you think I ran a campaign where white supremacists had a platform?" Conway asked.

One of Clinton's top campaign aides said they would rather lose the election than win the way Trump did. (Brian Snyder/Reuters)

The media's role

Top Trump staffers cited the billionaire businessman's "innate understanding" of the media as a major reason for his victory, crediting his unique ability to drive the news cycle and social media.

The coverage struck a nerve with his rivals, who argued that the media gave Trump benefits they didn't get.

At a panel on the media's role in the election, top Republican campaign managers heckled CNN's Jeff Zucker after the network president claimed that other candidates turned down interview requests.

Zucker stood his ground: "I understand that emotions continue to run high. That is not cable news' fault and that is not CNN's fault."

Trump's campaign argued that Clinton should have released all her emails to the public, nullifying some of their attacks.

Instead, Trump's deputy campaign manager David Bossie said her team "used the old Clinton playbook" by fighting off lawsuits asking to make her correspondence public.

"Is that the playbook you used on taxes?" asked Clinton campaign manager Robby Mook, citing Trump's decision not to release his tax returns.

Bossie shot back: "It was a winning playbook, I guess."

Trump's team defended their campaign strategy of not by issuing serious policy plans or establishing an extensive political machine but through 'branding.' (Mike Segar/Reuters)

Clinton's traditional strategy

Trump's staff argued that Clinton simply didn't work for it, citing their more active travel schedule coming out of the national conventions, and failed to motivate female voters despite her historic role as the first female major party nominee.

They also said that Clinton's understanding of the electorate was wrong, saying they used a model that projected turn-out more akin to the 2014 midterm races, when Democratic turnout was low, than President Barack Obama's 2012 victory.

Clinton's team attributed their defeat to a lot of factors — few self-inflicted.

Her aides argued that FBI Director James Comey's investigation, media coverage, the hacking of Democratic email accounts, gender bias and even Clinton's personal penchant for privacy and policy were to blame for her defeat. They accused Trump's team of peddling lies on social media websites of the alt-right, an increasingly common term for a far-right political movement normally tied to white nationalism.

"I don't think you guys give yourself enough credit for the negative campaign you ran," said Clinton strategist Mandy Grunwald, pointing to Trump's historic negative ratings and his team's trafficking in conservative media. "There was a very impressive gassing of her."

Palmieri said her only strategic regret was not pushing for a fourth debate, arguing that Clinton was strongest when she faced off on a stage with Trump. Mook admitted he regretted not putting more staff in Michigan, a state the Democrats lost narrowly. But Grunwald dismissed many of the post-game analyses: "It's all theoretic," she said.

Strategists on both sides of the aisle were struggling with a big question in the post-Trump world: Do the time-worn tactics of political campaigns still apply? Trump won, according to his aides, not by issuing serious policy plans or establishing an extensive political machine but through "branding."

"You guys took Donald Trump so literally and the American public didn't," Lewandowski said.

Clinton's campaign, saddled with a policy-wonk candidate, felt penalized for playing by the old rules. "This was the first sort of post-factual campaign and I think you were punished for telling the truth and being true to nuance," Mook said.