With references to Ronald Reagan, founding documents and American exceptionalism, night three of the Democratic convention sounded an awful lot like a Republican one.

If there was a subtext to the key message that Hillary Clinton would make a great liberal president, it was that Donald Trump won't make a good conservative one.

Former New York City mayor Michael Bloomberg — once a Republican now an independent — used his speech to tear into Mr Trump.

"There are times when I disagree with Hillary Clinton," he said.

"But let me tell you, whatever our disagreements may be, I've come here to say: We must put them aside for the good of our country. And we must unite around the candidate who can defeat a dangerous demagogue."

Vice-President Joe Biden reached out to the middle class that the reality TV star so often says he is fighting for.

"How can there be pleasure in saying 'you're fired?' He's trying to tell us he cares about the middle class? Give me a break!" he said.

Mr Biden's potential successor, vice presidential nominee and Virginia Senator Tim Kaine, delivered a much more direct plea to voters on the other side of the aisle.

"If any of you are looking for that party of Lincoln, we've got a home for you right here in the Democratic Party," Senator Kaine said.

He also had advice for any Bernie Sanders supporters considering a protest vote towards Mr Trump.

"We should all feel the Bern and we all should not want to get burned by that other guy," he said to rapturous applause and laughter.

Obama argues the difference between Reagan and Trump

Finally, President Barack Obama invoked one of the Republican Party's most revered figures to make his case.

"Ronald Reagan called America 'a shining city on a hill'. Donald Trump calls it 'a divided crime scene' that only he can fix," he said.

Sorry, this video has expired Obama says Donald Trump is not a "plans guy, or a facts guy either"

"He's betting that if he scares enough people, he might score just enough votes to win this election. That is another bet that Donald Trump will lose.

"We are not a fragile or frightful people. Our power doesn't come from some self-declared saviour promising that he alone can restore order.

"We don't look to be ruled. Our power comes from those immortal declarations first put to paper right here in Philadelphia all those years ago.

"We hold these truths to be self-evident, that all men are created equal; that together, we, the people, can form a more perfect union."

Trashing Mr Trump's conservative credentials won't win over the most hardcore Hillary haters, but it may give Republicans who don't really believe he is one of their own something to consider when they head to the polls in November.