Mitt Romney has emerged narrowly ahead of Rick Santorum at the Iowa caucuses, which traditionally predicts a favourite for the Republican Party’s presidential candidate.

With 30,015 ballots cast in his favour, or 24.6% of the vote overall, the former governor of Massachusetts emerged only eight votes ahead of Santorum, who received 30,007 (24.5%).

Ron Paul was placed third with 21.4%, Newt Gingrich fourth with 13.3%. Rick Perry and Michele Bachmann trailed with 10.3% and 5% respectively.

Iowa is the first of the states to hold its Republican party caucuses, where registered Republican voters make their choice for the party’s presidential candidate.

A similar process will now be repeated throughout the other states. The Democrats will hold caucuses but will not choose a candidate as President Obama is running for re-election.

While the results of the Iowa caucuses will usually indicate Iowa’s final choice of candidate, they do not consistently predict the national choice. In 2008, Mike Huckabee was most popular with state voters, but John McCain was ultimately selected to run against Barack Obama.

In the Iowa caucus of 2008, Mitt Romney came second. The former governor has opposed marriage equality for gay couples and civil unions, and signed the National Organization for Marriage’s 2012 Presidential Pledge, vowing support for a constitutional amendment banning gay marriage and preventing state judges from overturning what they deem to be discriminatory marriage laws.

In 2004, a year after Romney became Governor, the Supreme Judicial Court of Massachusetts ruled that gay couples must be allowed to marry, becoming the first state in the union to do so, in the sort of judicial action Romney has pledged to curtail.

In his 2008 campaign, he said: “I believe that traditional marriage is right for the nurturing and development of children, but that I do not want to discriminate against gay people in employment or housing or other parts of their life.”

Rick Santorum had experienced a last-minute surge in the race before placing second.

He has confirmed that if elected as president of the US, he would support a constitutional amendment that would invalidate existing gay marriages.

In an interview with NBC at his campaign headquarters for the Iowa caucus, he said there should be one marriage law across all states, and that he would support a federal amendment to the constitution which had the effect of dissolving existing unions.

Answering a question on whether gay couples would be forced to divorce under the amendment, he said “Well, their marriage would be invalid. If the constitution says ‘Marriage is this’, then people whose marriages are not consistent with the constitution…”

He shrugs as the interviewer then asks if that would be the only solution, to which he says he wishes there were “another way”.

Santorum has been vocal in his opposition to equal marriage rights. In July 2011 he said the political left were in favour of gay marriage because it was a “two-fer”.

He explained: “When you redefine marriage, you cheapen marriage. You make it into something less valuable, less special … [and] it is a sure bet that will undermine faith.”

Romney is a favourite to emerge ahead in the New Hampshire state primary on 10 January. It is rare for a Republican presidential hopeful to win both Iowa and New Hampshire, which traditionally favours more moderate candidates.