A few months ago, I highlighted the claims of a genuine longshot for the Presidency. My argument then was that he was a candidate who had not been damaged by the internecine warfare that had brought the party to the impasse it found itself in then. After all, they had done similar before, when they could find nobody among the leading contenders who could command the support of the Republicans in the House of Representatives. Eventually, they found someone who at first said he wasn’t interested but later relented.

They could also pick someone, I argued, who is currently next in line to the Presidency after Joe Biden. Or they could pick someone who had already shown a taste for the White House, running as recently as 2012 for the Vice-Presidency of the United States. In other words, I highlighted the claims of one man who combines all these characteristics. He is the Speaker of the House of Representatives, he is second in line constitutionally to the Presidency, and he was the running-mate of Mitt Romney in the 2012 Presidential election. His name is Paul Ryan, and he was trading at a healthy 500-1 to be the next President of the United States.

To a small stake, those odds looked very tempting. When Donald Trump secured the nomination of the Republican Party for President of the United States, it looked like the bet was lost, which is often the case with 500-1 longshots.

In the past few days, however, there have been some serious rumblings, going beyond the usual murmurs of discontent, about the viability of Mr. Trump as a serious contender for the Presidency, and equally a worry among mainstream Republicans that the alternative possibility, that he actually could be elected, was even worse.

But how likely is it that these rumblings could turn into something that could lead to the current nominee dropping out of the race? One way of estimating this is to assess the likelihood of the Republican Party winning the Presidential election in November, and compare this to the chance of Donald Trump winning the Presidency. A glance at the current Betfair odds separates these two probabilities by about 1.3 per cent. This can be viewed as a rough and ready estimator of the likelihood that a different Republican than Trump wins the election.

To this must be added the chance that Mr. Trump’s replacement loses the election. Currently the chance that the Republicans lose, using the same metric, is 77 per cent, so that is more than three times the likelihood they will win. Multiplying 1.3 per cent by this factor gives a probability of someone other Republican than Donald Trump losing as about 4.3 per cent. So the total likelihood of someone other than Trump winning or losing the election sums to 5.6 per cent.

Taking all variables into account, and adding a dose of personal judgment, I estimate that the chance of Trump being replaced on the ballot paper as Republican candidate is between 4 per cent and 8 per cent. At this stage of the race that replacement would, in my opinion, almost certainly be a respected member of the Republican establishment, untainted by the internal battles, and able to command broad support. I would estimate that Speaker Paul Ryan would be about a two in three chance of being that candidate.

On the basis of these estimates, I estimate that Ryan has about a 4 per chance of being on the ballot. If he is, I think he has about a 40 per cent chance of winning. This means that odds of greater than about 60-1 about Speaker Paul Ryan being elected the next President of the United States are starting to look like value.

At current best bookmaker odds of 66-1 (Bet 365, Ladbrokes), or slightly longer on Betfair, there is in my judgment a sliver of value, to small stakes, especially if you haven’t already taken the previously advised 500-1.

Paul Ryan to be next President - 1pt @ 66/1