Conservatives were convinced Mitt Romney was going to win the US election - they were wrong.

Conservatives were convinced Mitt Romney was going to win the US election - they were wrong. Photo: Getty

To the Republicans' dismay, and despite the polls indicating a close contest, Barack Obama won the 2012 US presidential race against Mitt Romney by a convincing margin.

The Democrats have expanded their majority in the Senate and gained additional seats in the House of Representatives, although perhaps not as many as was once thought possible. The Republicans' one area of success was managing to retain domination of the states' governorships.

For the moment the Grand Old Party is preoccupied with recriminations. How did this happen? The Republicans and their conservative allies were sure Obama was destined for defeat. But a potent mix of demographics, a steadily improving economy and a clear rejection of extreme conservatism, combined with GOP hubris, a superb Democratic campaign organisation, and Obama's huge advantage over Romney in terms of likeability, propelled the President and his party to victory.

In this election voters were offered clear choices: between main street or Wall Street; ''middle out'' economics or supply side economics; tax rises for the wealthy or additional financial imposts on the middle class.

Obama and Romney differed about whether Obamacare should be implemented or repealed; the future of Medicare and Medicaid, and restrictions on the availability of abortion services.

Ultimately Obama prevailed in because his key constituencies (young, minority, female) expanded in numbers and he held their support. The voters who showed up at the polls in 2012 were more likely to be minorities, younger and less conservative; an electorate that looks like the US of today, not yesterday. Obama won in vital states such as Colorado with minorities' support; 87 per cent of Hispanic voters in Colorado supported him.

In addition, he achieved historic levels of support among Asian-Americans, with 73 per cent voting for him, compared to 62 per cent in 2008.

In contrast, Romney lost the race because it was all he could do to hang onto the core party supporters and because, ultimately, voters rejected his policies on immigration and health care and were suspicious of his ability to empathise with their financial struggles.

The GOP is now parodied as the party of angry white men. Republican primaries have become Tea Party litmus tests that threw up candidates like Todd Akin, Richard Mourdock and others who espoused ideas about rape, contraception and ''self-deportation'' that alienated the electorate.

In this election, a number of winnable races for the Republicans were sacrificed on the altar of extremism.

Not everyone who voted for Obama necessarily subscribed to his core values and beliefs about a positive role for government in advancing national prosperity and individual opportunity.

But they did recognise the important impacts on families and communities of federal government initiatives like automobile industry bailouts, federal assistance after hurricanes and tornadoes, and the decision to help some young illegal immigrants stay in the US.

Of course the GOP will now try to shift ground, both to accommodate these changes in the electorate and to address their election loss. In the short term that could turn out to be very divisive. The mood may well be to turn further right.

The first test looms because Congress must deal with the need to address the 'fiscal cliff' before Christmas. This is the provisions of the Budget Control Act of 2011, which are due to come into effect on January 1 unless legislative action on budget and deficit issues is taken.

It is a test for Obama, too. Can the President do in his second term what he could not do in his first: end political gridlock in Washington and guide a divided political system to legislative consensus on the nation's most intractable problems?

In the first days after the election, the responses from Republican leaders have not been promising. Senate Republican Leader Mitch McConnell issued the challenge: ''Now it's time for the President to propose solutions that actually have a chance of passing the Republican-controlled House, and deliver in a way that he did not in his first four years in office.''

House Speaker John Boehner declared in a television interview that he would not make it his mission now to repeal health care reform, saying: ''Obamacare is the law of the land.'' But almost before these remarks could be reported they were taken back, with a spokesperson saying the Speaker and House Republicans ''remain committed to repealing the law''.

In his 2008 inauguration day speech, Obama was prescient in acknowledging that people would question the scale and scope of his ambitions. He countered with: ''What the cynics fail to understand is that the ground has shifted beneath them, that the stale political arguments that have consumed us for so long no longer apply.''

In 2012, the veracity of that statement remains, but now the ground has also shifted for Obama. He is now a second-term president, with the potential to be free from party politics as he considers his legacy. How will he use his second chance to show the nation, and the world, what he can do?

Dr Lesley Russell is a senior research fellow at the Australian primary health care research institute at the Australian National University.