A grim reality is emerging for Mitt Romney's presidential campaign. The polls that turned around so dramatically for the Republican candidate after the first presidential debate, and that slowed early last week, have stalled, leaving the President, Barack Obama, with a tiny but consistent winning edge.

The key states that have become known as Mr Obama's ''midwestern firewall'' are holding and few people aside from Mr Romney's supporters can confidently plot a way through it for the Republican candidate to win the 270 electoral college votes he needs to reach the White House.

The Real Clear Politics poll average found the Romney campaign lagging in Ohio, Wisconsin and Nevada on Saturday, states that would not guarantee a Romney victory if he carried them but would put Mr Obama over the line if he won there.

While some find Mr Romney ahead in Florida and Virginia, his margin is much narrower.

''There is just so much consistency in the polls now,'' said Robert Alexander, a professor of political science at Ohio Northern University.

Asked if Mr Romney could still win he said: ''It's possible. Anything is possible.''

According to the Real Clear Politics average of national polls, Mr Obama was ahead on Saturday by 0.1 of a percentage point, having trailed by 0.8 as recently last Monday.

Romney campaign sources concede hurricane Sandy stalled Mr Romney's momentum by focusing attention on the President, CBS News reported.

Karl Rove, whose two organisations vowed to spend $300 million supporting Republicans throughout the campaign, confidently predicted a Romney victory in his column in The Wall Street Journal on Thursday.

In an interview with The Washington Post on Saturday, he too was arguing that the storm had been a disadvantage for Mr Romney.

''If you hadn't had the storm, there would have been more of a chance for the [Mitt] Romney campaign to talk about the deficit, the debt, the economy. There was a stutter in the campaign. When you have attention drawn away to somewhere else, to something else, it is not to his [Romney's] advantage,'' he said.

Other analysts have noted that the storm's impact could depress the vote in affected areas, mainly Democrat strongholds, eating into the popular vote without affecting the outcome.

Far from giving up, Mr Romney has increased the tempo of his campaigning, with events in seven states scheduled between Saturday afternoon and Tuesday. At rallies on Saturday, Mr Obama and Mr Romney acknowledged the rigours of the campaign.

''You know I'm working hard because my voice is getting a little raspy,'' Mr Obama told a rally in Milwaukee.

Mr Romney said: ''We're almost home. One final push, we're going to be there … The door to a brighter future is there. It's open for us, it's waiting for us.''

He added some detail to his stump speech, telling the audience he would introduce a ''down payment on fiscal sanity'' bill that would ''cut government by 5 per cent from day one''.

On Friday night, Mr Romney and his family attended a rally in Ohio with his running mate, Paul Ryan, and his family, as well as key supporters - including the former secretary of state Condoleezza Rice, the former New York City mayor Rudy Giuliani and Senator John McCain - before they fanned out across the key battlegrounds.

Republicans have made the killing of four Americans at the US consulate in Benghazi, Libya, a central theme in the dying days of their campaign.

Mr Giuliani told the audience in Ohio that had Mr Romney been president, the attack might not have happened. ''Maybe if we had a president who was paying attention, we wouldn't be going through all of this investigation of what's being covered up about Libya,'' he said.

Senator McCain, a former prisoner of war, said that veterans were telling him they were ''sick and tired of a commander-in-chief who doesn't lead''.

A new intensity has become apparent in the crowds at Republican rallies.

The travelling press has been heckled with calls of ''do your job'', while on the routes into the events groups of supporters have been seen holding up placards about Benghazi.

- Sydney Morning Herald