With election day less than three weeks away, Hillary Clinton and Donald Trump have clashed in the final presidential debate. The two sparred over the direction of the Supreme Court, immigration, the economy, US foreign policy, and fitness to lead.

The Conversation’s experts were watching the debate with an eye across the candidates’ performances and the key policy areas. Their responses follow.

Did the debate change any minds?

Dennis Altman, Professorial Fellow in Human Security, La Trobe University

The final debate produced little that was new, little that was edifying, and probably changed very few minds.

Both candidates threw dirt at each other. Trump’s tactic was to deny. Clinton’s was to circumvent, as when she was asked about potential conflict of interest between her role as secretary of state and access given to donors to the Clinton Foundation.

In some ways this was the most substantial and least dramatic of the three debates, with genuine exchanges on policy. The questions covered the full gamut of issues facing a president, and the first 20 minutes drew predicable faultlines between the candidates on abortion, guns and immigration.

For a brief period it was possible to imagine this was another US presidential election, where both candidates accept the rules of the game and show some respect towards each other. That veneer proved flimsy.

Both questioned the fitness of the other to be president. Trump declared Clinton “should not be allowed to run”. He followed this up by refusing to say whether he would accept the results of the election, saying only he would “keep us in suspense”.

As Clinton pointed out, Trump has a record of calling foul whenever he loses, and his supporters are already calling the election rigged against him. Matt Bevin, the Tea Party Republican governor of Kentucky, has already said blood may need to be shed were Trump to lose.

The paranoid streak in American politics has never before reached the heights that it will in the wake of a Clinton victory, which looks likely.

Trump the wrecking ball

Nicole Hemmer, Assistant Professor, Miller Center, University of Virginia, and US Studies Centre, University of Sydney

There is exactly one thing that matters from the third debate: Trump refused to say he would accept the results of the 2016 election.

Never before in the history of American democracy has a candidate made the legitimacy of the results contingent on his own judgement. It is the most demagogic, dangerous statement made in a presidential debate.

What else is to be said? There was policy tonight – more than we heard in the first two – but it just doesn’t matter.

Trump’s thin-skinned reaction to his poor poll numbers – his conspiratorial fantasy of a rigged election that has zero basis in reality – endangers the most vital part of America’s representative democracy: the peaceful transfer of power from one party to the next. It has been breached exactly once, leading to the Civil War.

There will be no civil war following November’s vote, but the stakes are still quite high. Trump has become a wrecking ball smashing into the foundations of American democracy.

If nothing else, the third debate made clear the stakes of the 2016 election.

Trump ignorant on policy issues

Kumuda Simpson, Lecturer in International Relations, La Trobe University

During the final debate Trump once again demonstrated his startling ignorance on important policy issues – particularly on Iraq and Syria – and his propensity to brazenly lie about his past statements. Clinton, also once again, displayed her detailed understanding of those same issues.

Perhaps the most appalling moment was Trump saying he wouldn’t necessarily accept the election result – thus undermining the very bedrock of democracy.

While the third debate covered a lot of the same material as the previous debates, it also raised two important topics. Gun control and abortion rights are fundamental to understanding US politics.

Clinton and Trump declare vastly different views on these two issues. Trump is anti-abortion and pro-gun-rights. Clinton is pro-choice and in favour of “reasonable gun regulation”.

Since the 1973 Supreme Court decision in Roe v Wade, which declared abortion a constitutional right, conservative states across America have been aggressively legislating to restrict women’s access. Trump said if he were able to appoint several conservative justices to the Supreme Court they would absolutely overturn Roe v Wade. This would be a disaster for women’s rights to control their bodies and reproductive health.

Trump claimed he would hand legislative responsibility for abortion back to the states. We can already see the disastrous consequences of this, as many American states have already eroded what is a fundamental human right.

On gun control the difference was down to regulation. Trump is opposed to any regulation restricting particular types of guns or who can buy them. Clinton claimed she supported the Second Amendment, but with legislation that would close what’s known as the gun-show loophole and restrict access to certain types of weapons.

It is highly unlikely that either position would do anything to seriously tackle the staggering problem of gun violence in the US. Trump’s position certainly would not. Regulation is necessary and will help – but not solve – the problem.

The real issue here is gun violence in the US does not have one simple cause. It is a complex and multi-causal problem that deserves greater attention – and one that certainly was not going to be covered adequately in such a forum.

Debate all about character

Bryan Cranston, Online Lecturer in Politics, and PhD Candidate in Politics and History, Swinburne University of Technology

The third and final presidential debate passed with few surprises.

There was never any doubt as to who was going to win the debate. The only way Trump could have won would have been if Clinton wasn’t there.

Ironically, Trump only needed to perform slightly better than his two previous debate disasters to be considered as having done a good job. Naturally, any attempt to portray Trump as anything less than the unmitigated winner of the contest will be seen by his campaign and supporters as further evidence of a conspiracy by the mainstream media to deny him the White House.

With their response to the opening question, Clinton and Trump steadfastly staked their claims to their respective party bases. Clinton affirmed her support for abortion rights, marriage equality, and campaign finance reform, while Trump focused on the Second Amendment and gun control. This was less a debate and more about rationalising an appeal to core supporters.

Trump was less than affirmative on his position regarding abortion rights. In fact, he didn’t answer the question, which will no doubt anger many evangelical and religious conservatives.

The debate only got worse for Trump when the topic turned to Russia and national security. In a debate about policy, facts were always going to play a major role, and this is perhaps the most significant deficit in Trump’s campaign. Clinton refuted all of Trump’s attacks by citing evidence, while Trump resorted to rhetoric.

Despite attempts to make it about policy, the final debate was all about character. Each candidate talked about why the other was unfit to serve as president.

It was a nasty, personal demonstration of two people seeking the highest political office in the world. Who won? The winner was overwhelmingly clear, and it wasn’t Trump.