MANCHESTER, United States (AFP) - Democratic presidential hopefuls including Hillary Clinton used Donald Trump as a political bogeyman to highlight their own calls to defeat Islamic extremists without using the bigotry and bluster employed by their Republican rival.
Former Secretary of State Clinton, US Senator Bernie Sanders and former Maryland governor Martin O'Malley each hit on the need to boost national security, raise the minimum wage, protect rights of women, minorities and the disadvantaged, and prevent Republicans from rolling back economic progress as they faced off in New Hampshire.
The debate on Saturday (Dec 19) was their party's third of the primary election season - the last of 2015 and their first since the attacks in San Bernardino, California where a radicalized married couple killed 14 people.
But the candidates also took turns hitting the Trump punching bag, as they hurled outrage about the Republican's fear-mongering and recent controversial comments about immigrants - in particular, his call for a ban on Muslims entering the United States.
Americans, Clinton said, "need to make sure that the really discriminatory messages that Trump is sending around the world don't fall on receptive ears."
"He is becoming ISIS's best recruiter," Clinton said of the self-declared Islamic State extremist group, claiming that militants are "showing videos of Donald Trump insulting Islam and Muslims in order to recruit more radical jihadists."
O'Malley also offered a harsh rebuke to the "political danger" wielded by Trump and other "unscrupulous leaders (who) try to turn us upon each other."
The country will rise to the challenge of ISISbut only if Americans never surrender their values "to the fascist pleas of billionaires with big mouths. We are a better country than this."
Trump's apparent popularity has only grown in recent weeks since his most controversial remarks. The political neophyte tops most Republican national polls and is putting establishment candidates like Jeb Bush in knots.
While the Democrats united against Trump, they disagreed on foreign policy, guns and how to rein in Wall Street excesses.
Sanders clashed at length with Clinton over how to tackle extremism, opposing her call for a no-fly zone over Syria and for focusing on ousting that country's President Bashar al-Assad.
Clinton noted the recent UN Security Council's support for a political plan to end Syria's brutal civil war by summoning rebels and the regime to the negotiating table.
Sanders, who is more comfortable talking about economic inequality and financial abuse, topics that are the cornerstones of his campaign, was sceptical.
"The United States at the same time cannot successfully fight Assad and ISIS," he said. "ISIS now is the major priority. Let's get rid of Assad later."
Sanders paraphrased Jordan's King Abdullah in saying that "Muslims should lead the effort on the ground."
The self-described democratic socialist also reminded viewers of Clinton's 2002 vote when she was a New York senator authorising president George W. Bush's use of military force in Iraq.
Clinton insisted she too was not ready to send US boots into Syria and Iraq, saying she had a strategy to "combat and defeat ISIS without getting us involved in another ground war."
The debate unfolded amid a minor scandal between the Clinton and Sanders campaigns, with accusations that a data breach was carried out by Sanders' team against Clinton's.
The Democratic National Committee (DNC) temporarily suspended the Sanders campaign's access to a key voter database after at least one of its staffers took advantage of a computer glitch to peek at Clinton voter data.
Sanders filed a suit against the DNC to regain access to the data on Friday.
But on stage Saturday he apologised to Clinton, saying "this is not the type of campaign that we run."
And with Clinton accepting Sanders' apology, the issue rapidly deflated, and candidates turned to foreign policy and the economy.
Data and IT are uncomfortable topics for Clinton, who was the centre of an uproar after it was revealed she used a personal email account and server while Secretary of State.
Before the data breach the week had gone well for Sanders, whose supporters broke presidential campaign history by donating more than 2 million times to his campaign for the Democratic nomination. Clinton, who has raised much more money than Sanders, has depended significantly on large checks from big donors.
In national polls among Democrats, Sanders has 31 per cent support, a number that has remained constant since early November. Clinton's support is in the mid-50s.
O'Malley trails at less than 4 per cent.