Tense debate offers no clarity for Republicans

Donald Trump appeared flustered during repeated attacks over his views on Muslim migrants but refused to waver. Photo / AP

Lack of clear winners echoes uncertainty over who will claim party nomination.

The final Republican debate of the year featured sharp exchanges over national security, personal insults and regular interruptions, but in the end there were no outright winners.

In that sense, it was an almost perfect reflection of the party's unpredictable nomination campaign.

The two-hour session was as unruly as it was substantive. It dealt with some of the most serious issues of the moment but broke down in shouting and interruptions that seemed to underscore the determination of all the candidates to make their mark as the campaign heads into the holidays before resuming in January.

Donald Trump, who dominates the national polls, came under repeated fire for proposing to bar the entry of Muslims into the United States and for saying he would go after the families of Isis (Islamic State) terrorists.

Though appearing flustered at times, he held firm on his positions, seemingly confident that his harsh rhetoric continues to find support.

Former Florida Governor Jeb Bush, whose support nationally has eroded steadily, led the attacks against Trump, a sign of his resolve to make one more run at turning around a candidacy that has struggled for visibility.

More than any other candidate, he got under Trump's skin - but without a clear outcome.

Senators Ted Cruz (Texas) and Marco Rubio (Florida), who have been circling each other for weeks in anticipation of a final showdown sometime next year, argued over security, surveillance and the best strategy to defeat Isis but neither candidate scored a truly telling blow on the other.

The debate was singularly focused on matters of war and terrorism, coming at a time of heightened security concerns and on a day when Los Angeles schools were closed because of a threatened terrorist attack.

Republican presidential candidates Sen Marco Rubio, Ben Carson, Donald Trump and Ted Cruz (R-TX) on stage during the CNN republican presidential debate. Photo / Getty Images

The discussion enjoyed only one clear consensus: that President Barack Obama and Hillary Clinton have left the country less safe.

The conversation also revealed significant divisions within the Republican Party on issues that GOP voters now see as the most important for the coming election.

At some moments, the debate delved into arcane, though important, details of how to combat terrorist threats - touching on Isis fighters abroad, the possibility of homegrown terrorists becoming radicalised without family or neighbours knowing, the proper vetting of Syrian refugees coming to the United States, and how best to secure the country's borders.

At other points, the frustrations of a campaign that has defied predictions and expectations spilled on to the stage.

The exchanges between Bush and Trump were particularly revealing as a measure of how the race has unfolded in ways the former governor never expected. Bush sought to cast himself as the grown-up and Trump as an unserious candidate.

Trump, as has been his style all year, swatted back by talking about his strength versus what he said was Bush's weakness, comparing his front-running status in the polls with Bush's single-digit support.

The back-and-forth between Cruz and Rubio was far more substantive but with a political edge. Rubio's goal was to undermine Cruz's effort to consolidate conservatives of all stripes - Tea Party, evangelical and libertarian - by questioning whether he is as conservative as he claims.

Cruz's rebuttals were designed to paint Rubio as an establishment conservative, out of touch with an electorate that includes many voters angry at the party's leadership.

The exchange everyone was expecting - between Cruz and Trump - came and went with no points scored. Cruz had criticised Trump at a private fundraiser last week, suggesting that there were legitimate questions about whether the billionaire businessman had the judgment to be president.

When the issue was raised near the end of the debate, a smiling Trump mockingly warned Cruz not to attack. Cruz ducked the question, saying the voters will have to make judgments about all the candidates as to their qualifications, temperament and judgment.

The exchange everyone was expecting between Cruz and Trump came and went with no points scored. Photo / Getty Images

The debate marked the end of one of the most tumultuous and unpredictable years in American politics. Whether it was a harbinger of things to come or a false indicator of the state of the Republican Party is the question that will begin to be answered in six weeks.

The lineup on the stage highlighted how, in 2015, grassroots Republicans have rejected the governing class in favour of outsiders. Trump and Ben Carson, two non-politicians, and Cruz, an anti-establishment senator, stood together as a symbol of the electorate's fury with the established order.

Farther out on the stage were a series of elected officials - among them two governors, a former governor and two senators - who have struggled to find their balance in a year when records in office, governing experience and policy white papers have been given short shrift by rank-and-file conservatives.

What comes next is the question all of the candidates and many in the party leadership are asking.

Months ago, many Republican strategists assumed that the nomination contest would begin to revert to more familiar form as the primaries and caucuses neared.

But that was before Trump survived one controversy after another, the latest coming in the past week with his proposal to temporarily bar Muslims from entering the United States.

If recent polls are correct, Trump has weathered that storm as he has survived others.