People who back lawmakers based on their stance on a single issue can pressure incumbents to vote against the views of most Americans, new research shows, suggesting that national policy on hot-button topics could be dictated by a “tyranny of the single-minded.”

According to an article published on Jan. 23 in The Review of Economics and Statistics, U.S. senators seeking re-election in a tight race sometimes “flip-flop” on bills related to gun and environmental policy issues, playing to the preferences of single-issue voters rather than the majority of their constituents — a result which could explain why some bills don’t pass, even with overwhelming support from the public.

“Because single-issue voters see the policy space as unidimensional, they can use voting to punish and reward politicians for specific policies,” co-authors Laurent Bouton, Paola Conconi, Francisco Pino and Maurizio Zanardi wrote, adding that, “Instead of a tyranny of the majority, democracies may thus be afflicted by a tyranny of the single-minded."

The researchers hypothesized that vulnerable sitting senators are more likely to flip-flop as their next election season approaches, reversing course on stances they had previously taken regarding “secondary” issues — like gun control and environmental regulation — which only small groups of voters prioritize over all other areas.

Specifically, they predicted that Democratic senators would vote more “pro-gun” as elections neared, while Republicans would begin backing “pro-environment” legislation when facing parallel election pressures.

The researchers fed data on senators’ voting records into specially designed probability models, finding evidence that senators were significantly more likely to vote against their own prior positions on guns and the environment as they approached their potential re-election in a tight race. 

Comparing senators from the two major political parties, they found Democrats are up to 8.5 percentage points likelier to vote pro-gun in the last two years of their terms, while Republicans were as much as 2.2 percentage points more likely to vote pro-environment in the final two years of their mandates.

Similar effects weren’t found among senators who planned to retire, or those who held “safe seats” and weren’t likely to need votes from the single-issue camps.

According to the researchers, voters focused on environmental policy and gun rights protections are particularly influential because they represent a group that senators can win over, often without alienating an equally well-organized, hyper-focused opposition.

But that isn’t the case for single-issue voters concerned with abortion regulations, Zanardi told The Academic Times, noting that highly engaged constituencies on both sides of the policy divide make flip-flopping less strategically appealing.

The issue represents a “dynamic equilibrium” for incumbent senators, he said. 

“If I’m pulling you left and someone else is pulling you right, you don’t move — these two forces are keeping you in check,” Zanardi added.

While small groups devoted to single issues can shape the ways incumbent senators vote, the researchers found, they need to be the right size — “neither too small nor too large.” Otherwise, senators would be incentivized to either never deviate from earlier stances or take a different position from the outset.

The results show how a few voters hold politicians accountable on the issue that matters most to them, according to the researchers — sometimes at the expense of much larger constituencies who feel differently on the issues but don’t pack the same electoral punch.

“When it comes to secondary issues like gun control, the environment and reproductive rights, office-motivated politicians are only accountable to minorities of voters who are intensely about these issues, knowing that the rest of the electorate will decide whether to reelect them based on their stance[s] on other issues,” they wrote.

Bouton, Conconi, Pino and Zanardi cited the Senate’s failure to expand background checks for gun owners — despite polls showing 90% of Americans supported the bill — as just one example of the way a single-issue lobby can win out even when heavily outnumbered.

Zanardi said the team’s findings speak to the importance of a well-informed voter base, noting that single-issue voters who paid closer attention to their senators’ records over the long term wouldn’t be so easily swayed by strategic flip-flopping just before elections.

“A premise of this paper is that voters forget,” he said. “I vote for you because yesterday you voted for guns [for example], but I forget that three years ago you [took] a completely different position.”

“If I didn’t have a short memory problem … then you could not have fooled me,” he added.

The article “The Tyranny of the Single-Minded: Guns, Environment, and Abortion,” published online on Jan. 23 in The Review of Economics and Statistics, was co-authored by Laurent Bouton, Georgetown University; Paola Conconi, Université Libre de Bruxelles; Francisco Pino, University of Chile; and Maurizio Zanardi, University of Surrey.