MITT Romney faces four days that could make or break his bid for the presidency as delegates start to gather in Tampa for the Republican party convention, against a troubled backdrop of a tropical storm and a row over a Senate candidate’s comments on rape and abortion.

For Romney, who will be rubber-stamped as the party’s candidate at the convention, the event is crucial. Tens of thousands of Republicans will be in the Florida city, expecting him to deliver the speech of a lifetime on Thursday to an audience of more than 20 million and boost a presidential bid many fear is lacklustre, despite the fact that he is neck and neck in the polls with Barack Obama.

“I suspect I’m like a lot of voters in the middle who are still waiting to see some signs of life, humanity, conviction, personality, biography, vision. Just show me more than the one-dimensional ‘I’m not Obama’ campaign we’ve seen so far,” Mark McKinnon, a campaign adviser to George W. Bush and the 2008 candidate John McCain, wrote on the Daily Beast site.

Romney and his campaign team must now counter the image created by a $120m Democratic advertising onslaught over the summer portraying him as an ultra-rich businessman who made his fortune at Bain Capital off the backs of workers whose companies were closed.

Norm Ornstein, an independent analyst at the American Enterprise Institute, said: “The Obama campaign defined him before he had a chance to define himself.”

After the convention, the only guaranteed primetime events will be the three presidential debates with Obama.

Meanwhile, tropical storm Isaac could hit Tampa early next week, providing a less than ideal spectacle for a candidate still trying in vain to shake off the clouds of a row sparked by Missouri congressman Todd Akin’s comments on rape and abortion. Republican Akin earned a rebuke from Romney after saying that women’s bodies can prevent pregnancies in “a legitimate rape”. But he has so far rejected calls from Romney and his running mate Paul Ryan to exit the US senate race.

Yet the main problem facing Romney would appear to be one of profile. Although he has been on the campaign trail constantly since January, polls show many Americans have only a hazy notion of what he stands for. About 10 per cent say they have no opinion of him at all.

Conscious of the image of Romney as aloof, the campaign team say they and their designers have organised a schedule and put together a stage aimed at creating a sense of intimacy.

Republican officials showed journalists around the convention centre earlier, the centrepiece of which is a $2.5m backdrop, 13 giant cubes, each with a large-screen. Romney’s campaign team said he will attempt to turn his time at Bain into a plus, portraying it as evidence of his credentials for running the economy.

He will also confront another potential negative. Rather than downplay his Mormonism, as he has in the past, he will ask a member of the Mormon church to deliver the invocation on the day of his nomination speech, and Romney’s role as a bishop in the church will be highlighted.

Writing in the Wall Street Journal, Karl Rove, George W. Bush’s campaign strategist, said: “The moment is coming when what each candidate says about himself and his plans is more important than what he says about his opponent.”

Romney’s campaign team has organised a list of party luminaries whose main task is to talk up Romney. These speakers have only one mission: to build up an alternative profile of Romney to the one the Obama campaign has been creating.

Craig Shirley, the conservative author, emphasised the importance of Romney’s speech, scheduled for Thursday night. “It’s going to be his first introduction to all the American people, so he’s got to hit it out of the park,” he told Newsmax.

Part of the problem for the Republicans is that the Democratic convention follows them and then it will be Obama’s turn for three days of primetime coverage and a potential Democratic bounce.

About 35,000 Republicans have signed up to attend the convention. On top of this, thousands of lobbyists have paid for stands and will be throwing parties.

The dominant news of the day could be Romney formally passing the magic number of 1,144 delegates, the majority needed to make him the Republican presidential nominee. That would allow him to begin unleashing the millions of dollars he has been accumulating for his White House campaign. — The Guardian, London