The six candidates vying for the Republican Party's nomination for president have made an effort to differentiate themselves in their latest debate, a little over a week before their first major electoral test.

Each highlighted policy or personal differences they thought would make them appear unique in the crowded field.

Iowa goes to the polls on 24 January.

George W Bush continues to enjoy the support of 45% of registered voters in the state, according to the most recent survey taken by the Des Moines Register - the newspaper that hosted Saturday's debate.

His nearest competitor, publishing magnate, Steve Forbes, was favoured by 18% of respondents.

Tax tussle

Governor Bush has been in a war of words with challenger John McCain over competing tax proposals, and the two traded barbs about the plans.

Governor Bush said that Senator McCain's plan would eliminate tax-free benefits to working single mothers.

Mr McCain countered that, unlike Governor Bush's plan, he at least gave tax relief to the poor in his plan.

Mr Bush has forwarded a five-year $483bn tax cut plan, while Mr McCain has proposed a $240bn tax cut plan.

Sounding more like a Democrat than a Republican, Senator McCain said that the Texas governor's tax cut plan was too large and would spend a projected budget surplus without ensuring the future of social security, a public pension scheme for the elderly and disabled.

"When you run ads saying you are going to save social security, my friend, that's all hat and no cattle," Mr McCain said of the governor's tax cut plan.

The veteran vote

Mr McCain is polling a distant third in Iowa, in a statistical dead heat with conservative activist Gary Bauer and conservative commentator Alan Keyes, who has gained in the polls due to his strong showing in debates.

Mr McCain's third place is surprising in that he has chosen not take part in the Iowa caucus.

He has made New Hampshire key to his campaign, and has said that it would be a devastating blow if he were not to win.

Mr Bush and Mr McCain are running neck-and-neck in polls in that state, which will hold its primary on 1 February.

Senator McCain's campaign turns on two issues: His appeal to veterans and campaign reform.

The senator is a war hero, who served as a prisoner of war in Vietnam from 1967 to 1973.

He focussed on veteran's issues in several of his answers during the debate, including one involving the cost of long-term healthcare.

Mr McCain also continues to rail against the influence of money in politics, and even took a swipe at his own party.  

He said both parties had failed to enact healthcare reform because of contributions from interest groups.

He said trial lawyers had lavished money on the Democrats and insurance companies had done the same for Republicans.

Pro-life and anti-China

Mr Bauer took a different strategy in the debate, choosing not only to highlight his conservative Christian position but also by attacking China.  

"For 10 years, we have given China most-favoured nation (MFN) status, and they have given us the back of their hand," Mr Bauer said.

If MFN were revoked, Chinese goods would face greatly increased tariffs.

"We need a Reagan foreign policy," Mr Bauer said, "that would make national security and human rights higher priorities than trade."  

Mr Bauer held several positions in Ronald Reagan's administration, and he has actively tried to align himself with the party's patriarch.

Insiders and outsiders

Senator Orrin Hatch stressed his experience in Washington, which might not play well in a party that is quick to paint the federal government as heavy handed and out of touch.  

When asked a question about how to provide long-term healthcare, he was quick to point to a bill that he had written, and he repeatedly talked of his service as a high-ranking member of the Senate.

Mr Hatch said that many of his competitors' campaign pledges sounded promising but that they lacked the experience to successfully shepherd them through Congress.  

His comments stood in stark contrast to comments from Steve Forbes and Alan Keyes, who have worked hard to paint themselves as Washington outsiders.  

Mr Keyes called recent health care reform efforts "as another excuse for government domination".  

And in response to a question on education, Mr Forbes said: "The more the federal government gets involved in education, the more of a crisis we will have."