By Michael Ganslmeier, Assistant Professor in Computational Social Science, University of Exeter
Can a simple promise shift voter behaviour—even across ideological lines? That’s exactly what happened in Germany’s 2013 election. A pension pledge from the centre-right CDU/CSU party attracted a surge of support from women who stood to benefit, many of them previously loyal to the centre-left Greens. But the support didn’t last.
In a new study, I track the short-lived effects of this campaign promise using a rare natural experiment and high-quality German survey data. The results speak to a wider story in European politics: the power—and the limits—of welfare promises in today’s volatile electoral landscape.
Promising Pensions, Reaping Votes
The CDU/CSU’s promise, known as the Mütterrente, offered extra pension credits to mothers whose children were born before 1992. Crucially, this eligibility rule created a sharp line between those who would benefit and those who wouldn’t—based entirely on birth date. This meant I could compare otherwise similar voters and isolate the effect of the campaign promise alone.
Using the German Socio-Economic Panel (SOEP), a large longitudinal survey, I analysed voting behaviour among mothers just on either side of this eligibility cutoff. The results were striking: women eligible for the pension boost were 12.7 percentage points more likely to support the CDU/CSU during and immediately after the campaign.
This was not just a statistical blip. The effect was large, significant, and politically meaningful. It showed that even one-off, future-oriented benefits can persuade voters—especially if they are economically insecure.
A Temporary Political Realignment
But here’s the catch: the effect didn’t last.
By 2017, alignment with the CDU/CSU among eligible women had returned to pre-reform levels (see Figure 1). The promise had done its job—securing votes during a tight election—but once fulfilled, its influence faded. This wasn’t a lasting ideological shift. It was a political coupon: valid once, quickly discarded.
Interestingly, most of the CDU’s gains came at the expense of the Green Party. The Greens appeal strongly to middle-aged, middle-class women—exactly the group targeted by the Mütterrente. But there was no similar defection from the centre-left SPD. This suggests the pension pledge worked not by winning over the undecided, but by pulling voters from a direct rival.
Crucially, the promise did not increase voter turnout. It persuaded—but it didn’t mobilise. Voters already engaged in politics were willing to shift their support. Those outside the system stayed home.
Figure 1: Treatment effect (ATT) of the benefit promise on alignment over time. Note: The outcome variables are binary variables indicating alignment with the pledge-making (conservative party, coloured in black) and one non-pledge-making (the greens, coloured in green) party. All estimations include the following set of control variables: age, binary for being married, number of children in household, binary for no educational degree, personal income, years of work experience, satisfaction with household income, as well as the running variable. Each estimate is based on the baseline specification and uses a 3-year survey period (x-axis). The grey area represents (approx.) the period when the pledge was made. Confidence intervals are based on robust standard errors. The thick and thin lines represent 95% and 99% confidence levels, respectively. N2012-14 = 2481.
Why Some Voters Are More Persuadable
The biggest effects appeared among economically vulnerable mothers: those earning less than €850 a month (the threshold for “mini-jobs”), single mothers, and those with multiple children. In this group, support for the CDU/CSU jumped by nearly 28 percentage points.
This makes intuitive sense. For voters with tighter household budgets, a future pension boost—even years down the line—can offer tangible hope. Parties looking to make short-term gains would do well to remember this. Welfare pledges aimed at the most financially insecure are more likely to yield votes.
At the same time, this raises an ethical concern: if parties use the welfare state as a campaign tool, what happens to long-term policy planning? Are pledges made with governing in mind—or just winning?
What This Means for Parties—and for Democracy
These findings highlight three broader lessons for political parties in Europe and beyond:
- Campaign promises work—but only while they’re fresh.
Voters respond to targeted welfare pledges, but the effect wears off quickly once the promise is fulfilled. This makes promises powerful—but fleeting—tools of persuasion. - Welfare pledges don’t create new voters—they shuffle existing ones.
The Mütterrente didn’t bring new voters into the system. Instead, it shifted the preferences of those already voting—often by pulling them from rival parties. This is tactical success, not structural change. - Future benefits can sway the present.
Even though the pension supplement would only be paid out years later, it still influenced middle-aged mothers’ voting behaviour. This shows that immediate material gain isn’t necessary—credible promises can be enough.
But these dynamics also pose a challenge for democratic accountability. If parties compete by offering ever more generous social benefits to specific groups, political debate risks becoming a bidding war rather than a discussion about long-term policy goals.
The danger isn’t just fiscal—it’s democratic. When politics becomes transactional, time-limited promises can crowd out genuine debate, reducing elections to bids for economic favor rather than contests over vision, values, or long-term policy direction.
From Incentive to Instability?
The German case is not unique. Across Europe, from Italy to Sweden to the UK, parties of all stripes have turned to social spending pledges to win votes. And as economic insecurity rises, these promises are likely to become even more common.
But if welfare promises are increasingly used to tip elections, rather than build lasting coalitions or tackle inequality, the welfare state itself risks becoming a political tool rather than a policy framework. Short-termism may triumph over sustainability. And voters—if they come to expect constant rewards—may become harder to persuade without ever-increasing offers.
That’s the paradox: the very thing that makes campaign pledges effective also makes them unstable.
Keywords
Campaign promises, voter behaviour, welfare state, pensions, electoral strategy, economic insecurity
Michael Ganslmeier is Assistant Professor in Computational Social Science at the University of Exeter. His research focuses on causal inference, voting behaviour, and the politics of social policy. Website: www.michael-ganslmeier.com | Twitter: @ganslmeierm
📘 Read the full article in Comparative Political Studies: https://journals.sagepub.com/doi/10.1177/00104140251342928