The prospective First Gentleman makes persuasive case for his wife

A little of the old Clinton magic is lighting up the campaign trail in Nevada. Not Hillary Clinton's magic – she may be formidable in her own right, but still comes across to most audiences as awkward and carefully calibrated – but rather Bill's.

As the next round in the bruising Democratic nomination battle looms today in the land of casino neon and desert retirement homes, the former president and prospective First Gentleman has been in his element. He has torn through schoolhouse meetings and convention halls to plead the case for his wife with his trademark charm, razor-sharp intelligence and an unwavering ability to distill his points into a few expertly crafted catchphrases.

At a meeting in Henderson, a sprawling suburb 10 miles south-east of Las Vegas, Clinton hammered home the familiar talking points – that Hillary has the most experience, and the best track record of achievement – with a freshness and an enthusiasm that had the staid, mostly middle-class, white audience leaping to its feet. He had just come from a very similar meeting in Boulder City, another few miles towards the Arizona border, and was racing to address a Latino rally in Las Vegas, but Bill didn't care: he was loving the chance to talk, and feeding off the excitement he was generating.

"Even if I had never been married to Hillary," he said, "and she asked me to campaign for her, I would do it in a heartbeat." He then proceeded to explain why: she had fought for children and health care since she was a student; she had proved effective in the Senate despite a singularly hostile Republican-dominated environment; and she had shown an ability to keep pushing even in the wake of failures, like her ill-fated attempt to reform the American healthcare system in the early 1990s.

Neither of the other two main candidates, he said, had anything like her record of achievement. "The presidency is about making changes in other people's lives," he said. "What do you want in the end? A world-class change-maker, or someone who's just a change?"

Bill Clinton is, of course, only one factor in a highly complicated race in Nevada whose outcome nobody is daring to predict. One opinion poll earlier in the week found a virtual three-way tie between Clinton, Barack Obama and John Edwards. Yesterday, the Las Vegas Review Journal put Clinton nine points ahead of Obama, with Edwards trailing badly. It's impossible to tell which picture is more accurate.

Evidence from the campaign trail suggests Mr Obama is attracting the biggest crowds, and he has the key endorsement of the 60,000-strong Culinary Workers union, a major player in state politics which rarely backs the wrong horse. Mrs Clinton, meanwhile, has the state party solidly behind her, along with the teachers' union. She has been ahead in the polls for months.

Mr Edwards, though, refuses to be counted out – he's still regarded as the most pro-union candidate in a state with a strong union movement – and his campaign reports voters contacted by phone backing him by a 2-1 margin in the past couple of days.

He held a raucous, impassioned rally at a Henderson union hall the day before Mr Clinton's appearance, and his call for reversing the erosion of middle-class stability has great resonance in a state with the highest home mortgage foreclosure rate in the country. Talk to ordinary Nevadan Democrats, and it quickly becomes clear they are unsure who to opt for or even if they'll make it to the polls. Nevada is holding a caucus, not a primary, which means voters have to show up in person at 11am sharp this morning. That whittles the electorate down to the most committed.

The back-and-forth on the campaign trail has been as confused as the emerging picture. The Clinton and Obama camps fought furiously over a plan, approved months ago by the state party, to set up at-large caucus sites in a handful of the big Las Vegas casinos. Back-and-forth sniping has continued this week over a host of issues, but anecdotal evidence suggests that this does not impress voters. More significant, perhaps, is the quality of the surrogates campaigning on the candidates' behalf. If so, Bill Clinton is quite an asset. He hasn't been perfect in the past few months but the audience in Henderson, at least, was in no doubt. He still has the golden touch.