The success of political campaigns prior to the election is often measured by the amount of money raised from donations. But is such a metric really indicative of how well a candidate is doing? Ben Krauss, editorial assistant at Slow Boring, contends, “Presidential campaign donations are subject to diminishing marginal returns.”

That’s largely because the two candidates running for president are incredibly well-known, and seem to have incredibly calcified political support. While their campaigns and associated groups will be spending their money on a wide variety of functions, the most expensive and more important method of persuasion is advertising. And the relevant polling data and academic literature suggests that in elections like this one, it’s really just incredibly hard to change voter opinion.

Krauss asks, “How effective are presidential campaign ads, really?”

The effectiveness of presidential campaign advertising is literally a multi-billion dollar question, and has been the subject of extensive research.

In 2021, the American Political Science Review published a study by John Sides, Lynn Vavreck, and Christopher Warshaw that compared election outcomes between 2000 and 2018 in areas where Democratic ads outnumbered Republican ads to outcomes in neighboring counties that saw comparatively fewer ads.2 They concluded that if a Democratic presidential candidate aired 100 more ads in a given television market over the final 64 days of an election compared to their opponent, they would gain a 0.018 percent increase in their support. The absolute maximum vote gain they could expect, even if they aired significantly more ads than their opponent, was 0.5 percent.

Yale political scientist Alexander Coppock led a study in the 2016 presidential election that analyzed a representative sample of 34,000 people who were shown a series of 59 randomized ad experiments. They found that not only are most ads fairly unpersuasive, the “weak effects are consistent irrespective of a number of factors, including an ad’s tone, timing, and it’s audience’s partisanship.” Overall, the impact on voters candidate preferences ended up being a measly 0.007 percent. It’s hard to persuade people to change their minds (just check out the comment section on any Slow Boring article), and people are instinctively skeptical of paid advertising.

So, what does this mean for 2024?

Earlier this year, before the debate sent Democrats into an existential tizzy and the GOP began fantasizing about one of the largest electoral landslides of the 21st century, Trump was clinging to a small polling lead, and Biden was banking on his sizable cash advantage to close it.

Obviously, that did not happen.

Starting in May, the Biden campaign and its associated political groups did massively outspend the Trump campaign. And by the end of June, right before the catastrophic debate performance made things even worse, his polls generally did not meaningfully improve.

And don’t forget the results of the 2016 election.

Back in 2016, Hillary Clinton famously outspent Trump by a two-to-one margin. And Trump, even more famously, won the race.

I think this is largely because Trump was already an omnipresent figure in our media, and he frequently appears to voters in many forms that are not paid media. Perhaps his ad team will conduct a ton of ad testing and move the needle by an exceedingly small margin and swing certain battleground states. It’s hard to be sure. But the polls show that he’s going to win those states by a margin that is outside the reach of even the best performing ads. And his exceptional level of press coverage will compete with any carefully curated ad that his campaign might deploy. As a result, I think his swell of new mega-donors might be better off contributing their sizable fortunes to other candidates.

Krauss concludes that donations from mega donors aren’t so much about moving the voting needle as they are about ingratiating themselves with a future administration.

Ultimately, these donors probably don’t care how the money is spent, it matters more that everyone knows that they spent it.

Read the whole thing here.