I’m seeking opinions on this question. I'm veering towards a negative answer to this, but I could respect contrary views.

***What is it?

The somewhat unfortunately named Brexit Justice Ltd (headed by an individual called Marcus Ball) is prosecuting Boris Johnson MP for misconduct in public office. Johnson is claimed to have lied in the run-up to the Brexit referendum by saying that the UK sends £350 million of public money to the EU, but he knew (according to the case) that these claims were false. It’s not really about Brexit, it’s about honesty in politics.

There is currently a crowdfunder, which can be found here: https://www.crowdfunder.co.uk/ballvjohnson

The website for the organisation itself can be found here: http://www.brexitjustice.com/

***What are the possible outcomes?

• The case has got as far as Boris Johnson being summonsed to court (it’s not clear whether he has to be in court in person yet, as far as I’m aware)
• The court may find Johnson to be guilty – I don’t know what sentence would be imposed on Johnson in that case, but there is precedent for prison time (a police officer was given a year in prison for a lie which had much less ramifications than the Boris Johnson case)
• The court may find Johnson to be not guilty

***To what extent will this case make politicians more honest in the future?

If the court finds Johnson guilty, this would set a precedent against cases of serious lying. (note that if a politician said something without knowing it was untrue they wouldn’t get in trouble, similarly saying a lie just once would be unlikely to result in prosecution – they would need to repeat the lie). 

This precedent would apply in England and also, to a certain extent, other countries which have similar legal systems, such as Australia, New Zealand, India, Pakistan.

(If anyone thinks that this would be higher impact in other countries (e.g. the US?) then do say so and I can have a word with the guys at Brexit Justice and recommend that they do something in another country next.)

If the court finds in Johnson’s favour, might it embolden politicians to be less honest in future? This may be a risk, but note that this case at least shows that they are at risk of being summonsed to court, which is already something most people would be averse to.

Another argument in favour of donating is that if the case gets this far but then fails because of lack of funds, it may encourage politicians to be worry less about their risk of prosecution. (although if you buy the argument about the risk of a summons already being disincentive enough, then this argument shouldn't sway you)

The case can only have an influence on politicians’ behaviour if they know about it. The case has received substantial amounts of press attention recently in the UK, so I suspect politicians will be aware of this case.

***How likely are the courts to find Johnson guilty?

I don’t know enough about the legalities to have a strong opinion on this.

However I do know that Brexit Justice is employing a high-profile legal team, including the QC which worked on the Gina Miller case (which was successful). So it probably has a credible chance of finding Johnson guilty.

***How much better is the world if politicians are more honest?

This is not obvious.

It’s not obvious how much of a difference it would make to election outcomes. After all, when voting for a politician, are people influenced by the details of what politicians say, or is it more about how they come across, including their body language, and the values they espouse? So maybe honesty won’t make much difference here, perhaps?

Honesty of politicians isn’t just about the run-up to elections though.

Some believe that wars have started because politicians have used deception to get the public onside, including (some would argue) the Iraq war and Hitler’s invasion of Poland. Would politicians be less likely to use misinformation to start wars if the court finds in favour of Brexit Justice?

Or maybe if politicians want some bad outcome to happen (like a war), politicians would simply resort to using the truth with a bit of “spin” on it to get the outcome they want.

On balance, I think the world is better if politicians are more honest, but it’s not clear how much better.

***Costs

I think a reasonable estimate for the total cost of the work is £650k (but I might not be interpreting the figures entirely accurately)

The crowdfunder is for £500,000, but I suspect the total cost of the prosecution might include some other costs which have already been incurred, so the total cost might be a bit higher. I took a quick glance through the spending report on http://www.brexitjustice.com/about.  (i.e. this file: https://uploads.strikinglycdn.com/files/3446e816-6bb7-4203-aaf2-673a192daea4/Brexit%20Justice%20Financial%20Spending%20Reports%201-4%20summary%20(2).pdf) I would guess that the total spend listed there is £150k (but that's just based on quickly glancing through, not a proper adding up). I've assumed that there is no crossover between this past spend and the £500k for the crowdfunder. I've assumed that a future crowdfunder won't be needed. (The last assumption might make a material difference if it's wrong)

At first glance this may seem expensive. However this is because lawyers are expensive. (there is more on this topic on the crowdfunder page). There seems to be little scope to bring about material efficiencies here.

***What is the opportunity cost of this money

If all of that money had instead been donated to Malaria Consortium, we should expect something like 325 life-saved-equivalents* (See footnote). 

Note that it would be an error to take this figure (based on GiveWell cost effectiveness analysis) too literally, but it's a useful ballpark estimate. This then leaves us the question: would we rather have a world with more honest politicians, or save a few hundred lives? This is a hard question.

Using this estimate as the opportunity cost is a bit harsh on Brexit Justice. Many of the contributors are actually not trying to optimise their philanthropy. Arguably therefore there is some leverage here, because the counterfactual on their money is that without the Brexit Justice campaign they would have simply spent the money on themselves or saved it.

If you believe this leverage argument, you could argue that it's really only your own money (and maybe a small number of other contributors) whose counterfactual is a high-impact choice, and therefore a donation of (say) £2,000 would mean that the opportunity cost is only 1 life-saved-equivalent.

Note that this argument depends on the assumption that the crowdfunder wouldn't be fully funded without your donation, which leads us onto the neglectedness discussion.

***Neglectedness

The man running this campaign is not well-connected with lots of wealthy people.

Having said that, the significant press attention garnered may be sufficient to gather a large number of small donations. Indeed at time of writing almost 10,000 individuals have contributed to the crowdfunder already.

I'm not sure how long that crowdbacker campaign has been running, but the earliest update is from November 2018 (see https://www.crowdfunder.co.uk/ballvjohnson/updates?page=4#start) so I guess the crowdfunding campaign has gathered 10,000ish donations in around 6 months or so, and gotten more than half of the way there.

This is looking relatively successful for a crowdfunder, which often have contributions bundled together near the deadline. 

On balance I'm getting the impression that this is not a neglected donation opportunity (although this is driven somewhat by gut feel)

***Conclusion

There is a strong element of subjective judgement in this decision. On balance, I think that this donation opportunity underperforms a GiveWell recommended charity, and I think this largely because I don't think it will be neglected. 

However if you believed that the case will fall apart without your donation, then the decision becomes harder, and you might believe that this becomes a higher-impact choice in that case.

I think the strongest argument in favour of donating is if you donate from your not-optimal-philanthropy budget. I.e. imagine you split your funds into a do-the-most-good-you-can budget and other budgets. Donating to this from another budget would be appealing: it's a fascinating case, and I can see the temptation to be a part of it.

Full disclosure:

I met Marcus (the man behind this) some years ago when he first started working on this, and have met up with him socially a few times since. We have not met up often enough to count as close friends, but we are at least on friendly terms. I do not feel this personal connection is material enough to exert a strong bias on my opinions, however some risk of bias remains.

*Notes on life-saved-equivalents: Malaria Consortium chosen because it is the charity which comes first in the list on GiveWell's page (and their ordering is not accidental). Cost of £2000 for a life-saved equivalent comes from the Results tab of GiveWell's cost-effectiveness analysis, after applying the USD/GBP exchange rate from google. https://www.givewell.org/how-we-work/our-criteria/cost-effectiveness/cost-effectiveness-models/changelog-2019#Version_3_Published_March_21_2019 Note that GiveWell argues that the cost-effectiveness analysis should not be taken too literally