There is always something a little different about politics in Florida, and this year, one TV spot in particular captures the energy and unpredictability.
Watch it with the sound off and it appears conventional enough.
We see a still of the candidate - a Democrat - and then we see the face of the president beside him. It tells the voters of South Florida that the candidate is a man with a direct line to the White House and friends in high places.
It is a common enough practice in tight races where the presence of a political big-shot can tip the balance.
What makes the ad unusual is that it is paid for by a Republican candidate, Allen West and he is gambling that Mr Obama's intervention in the race will be a plus for him and a negative for his Democratic rival, Ron Klein.
It is true that the nature of the event the president attended does not help the Democrats - Mr Obama came to town for a fundraiser which Mr West sharply characterises as a "closed-door" event for "high-rollers".
But the bottom line is simple. Back in 2008, no Republican dared to hope Barack Obama would be anything other than a huge asset to any Democratic candidate.
Now, of course, it may be that Mr West is wrong - but there is no doubt that the Obama brand is not what it was.
The biggest single factor contributing to those declining ratings is the economy. There is an iron rule in American politics that when unemployment is high, as it is here in Florida, the presidents gets a pummelling.
But there is more to it than that. Somehow the two signature achievements of Obama's first two years in the White House are being made to feel like electoral liabilities.
Largest swing state
Republican candidates point to the cost of the stimulus programme and to the way healthcare reforms may subtly change the relationship between the federal government and the American people.
Democrats see those warnings as grotesque misrepresentations of what they have actually accomplished but they are not proving effective at countering the accusations.
A retired union official, Tony Fransetta, who now leads the Florida Association of Retired Americans, is frustrated.
"Too many of the things that Democrats should be taking credit for have been labelled as bad," he told me.
"The biggest mistake Obama made was to spend a whole year trying to work with Republicans, and Democrats haven't had the courage of their convictions or the stamina to challenge Republicans."
In the town of Davie, just inland from the port of Fort Lauderdale, I watched the debate between the three candidates for the Florida seat in the US Senate which is up for grabs.
Politics in Florida is not quite like politics elsewhere in America. It is the largest swing state for one thing, and the large number of elderly voters who retire to the sunshine of the south gives it an unusual demographic.
But its Senate race does neatly crystallise the way the mid-term race in general is shaping up.
Democrat Kendrick Meek is struggling. He is an Obama loyalist who has not left himself the political room to distance himself from the White House.
I could not help noticing at one point, though, that when he mentioned campaigning with a president, he was talking about President Bill Clinton, rather than Barack Obama.
The real race is between Governor Charlie Crist, a snowy-haired, perma-tanned veteran and the much less experienced Marco Rubio, official candidate of the Republican Party.
For a long time it seemed that the Republican nomination would be Mr Crist's but he was eventually forced to run as an independent when it became clear that Florida voters were in the mood for red-meat conservatism rather than the governor's nuanced pragmatism.
Just under two years ago, in the depths of the financial crisis and at the height of Obamamania, Mr Crist appeared on stage with the president and gave him a clumsy sort of man-hug.
Big mistake. As it turns out, Florida conservatives are not in the mood for bipartisanship.
He may have made the fatal mistake of reaching out across the aisle enough to annoy Republicans without reaching far enough to attract the Democrats whose votes he now needs.
His supporters outside the hall were indignant that the issue was being used against him: "Charlie just did what was right for Florida," one said.
But Mr Rubio's supporters, louder and younger, were having none of it.
"Marco is the only proper conservative in the race," I was told more than once.
"Obama is a socialist and Marco Rubio is going to go to Washington and fight for lower taxes and smaller government."
There was a time when Florida tended to appear on the lists of states where Republican primary voters had thrown away winnable races by choosing candidates more for their ideological purity than their electability. (Delaware is another.)
But either Mr Rubio is made of sterner stuff than anyone realised, or a lot of experts are going to be surprised by the strength of the conservative reaction to Mr Obama's first two years in office, because at the moment he is winning by miles.
Incidentally, there was no outright victory in the debate - there rarely is these days when the candidates are so carefully rehearsed and so cautious.
But the Senate race will produce a real winner and if that is Marco Rubio, then the Sunshine State will suddenly be a dark place for Democrats