We are five weeks out from the Democratic Convention, by which time Joe Biden's choice of running mate will be confirmed. Until that happens, we have a fascinating and unpredictable market to consider.
Are market signals a good guide?
Kamala Harris remains favourite although the California Senator has drifted slightly to 2.466/4. Whether her market status is telling, however, is a known unknown.
Harris was always a logical candidate. A well-connected, experienced Senator who fits the bill as a potential president, suitable for stepping up in a crisis. A woman of colour, former rival in the primaries, now an enthusiastic surrogate, who would bring plenty of big donors to the table. It doesn't require inside information or any specific expertise to price her short.
I am sceptical that anyone playing this market has an inside track. Rather, it is moved by rational calculation and stories in the media. I'm reminded of the wall of money backing John Kasich to be Trump's running mate in 2016. This despite being arch-enemies - the Ohio Governor even skipped the party convention and refused to endorse him. For most of the build-up, eventual pick Mike Pence was an outsider.
Duckworth the latest big gamble
If we are to read anything into the betting, Tammy Duckworth may be the one. Large sums for a side market have recently added fuel to an already significant gamble - she's now 7.413/2 from a peak of 120.0119/1 and nearly £3,000 is queuing up to back her at 7.613/2.
In truth, Duckworth is one who escaped my attention when building numerous back and forth positions. She is a woman of colour and her backstory - losing both legs whilst serving in Iraq - is formidable. However, I'd never heard her discussed as a 'president in waiting' and, like Harris, she represents a safe Democrat state rather than one of the decisive 'toss-ups'.
Nevertheless, she is plausible. Duckworth has become embroiled in a high profile spat with Fox News host Tucker Carlsson, after he called her a 'coward' who 'hates America' for being open to dialogue about removing statues of slave owners. She countered by telling Carlsson to 'walk a mile in her legs'. This is precisely the sort of fight Trump would be insane to engage in. Veterans are a core, loyal part of his base.
My instinct is generally that fights involving women targeted by Trump and Fox will play positively for Democrats. This was part of my earlier thinking regarding Gretchen Whitmer, after her fights with the White House over Covid help and lockdown in Michigan. However her chance seems to have faded following the George Floyd murder and protests, on the assumption that Biden would pick a woman of colour.
Rice perfect for fight over Russia
Likewise, I can very much see Biden wanting to have Susan Rice take on her critics on a big stage. She is a former UN Ambassador and National Security Advisor to Barack Obama. She would cement the Biden ticket's brand as a return to the normality of that relatively popular administration, and is experienced enough to assume the top job.
Picking Rice would amplify Trump's 'Obamagate' conspiracy theory - that the previous administration illegally spied on his campaign. This would be another very stupid fight to pick. It is the NSA's job to identify foreign agents such as Michael Flynn and Rice played that investigation by the book. Basic investigation of 'Obamagate' shows a US administration doing its normal job of guarding against national security risks.
Moreover, Rice has intervened with interviews and op-eds on Russia, and the unresolved scandal that Trump has done nothing to counter or protest to Putin about bounties being placed on the heads of US soldiers. I would urge the Biden campaign to relentlessly discuss it, accuse and expose the administration's negligence. They have no defence.
The rise of Rice has come at the expense of my best result, Val Demings. I haven't altered the views laid out recently - that a black, working-class woman, former Orlando police chief from the ultimate swing state of Florida would be electoral gold. I still think Demings is in the hunt and note the market has written her off before, only to bounce back.
Elizabeth Warren is also in contention, almost certainly shortlisted. Progressives have united around her and it is known that Biden would have picked her if running last time. I think she is certain to be very prominent in his administration, perhaps Senate Leader, but there is a massive negative regarding the VP role. It would mean temporarily handing her seat over to a Republican.
Grisham could fill gap with Hispanic voters
Others have moved up. Karen Bass - a Californian Congresswoman whom many say would fare best attracting black women voters - has been matched down to 10.09/1 from 200.0199/1. New Mexico Governor Michelle Lujan Grisham is the top Hispanic candidate at 36.035/1 and would make sense as Biden is underperforming with this segment of voters.
I'm less convinced by the claims of Atlanta Mayor Keisha Lance Bottoms. Her profile rose off the back of her impressive response to protests, but I doubt there was ever much of a faction among Team Biden for her. Stacey Abrams does not appear to have ever been in serious contention, despite her turnout-raising potential. I've laid both, along with both Michelle and Barack Obama, Mitt Romney, Bernie Sanders and Hillary Clinton. All name recognition candidates with little or no chance.
What are Biden's priorities in a candidate? I thought, prior to the Floyd murder that was used by opponents to destroy her chance, Amy Klobuchar was in pole position. That would suggest Biden is most concerned with having a VP whom he agrees with politically, and who won't scare off Republican converts. Also that he doesn't fear picking a rival.
That would be a positive for Harris and Warren but equally, both have political baggage and would be easier to paint as the 'radical Left', as Trump will.
In contrast, that line of attack won't wash with Rice, Demings or Duckworth - all of whom are on the same political page as Biden. My advice to his campaign would be to emphasise Russia, whilst undercutting Trump's preferred dividing lines. My advice to punters is to focus on that trio, either by backing them all or laying the main rivals and aforementioned no-hopers.
Follow Paul on Twitter and check out his website, Political Gambler.