Introduction: You've seen it countless times—candidates make promises during elections, but not all follow through. This article explores why some parties are more reliable than others when keeping their election commitments.

Methodology: We analyzed over 20,000 pledges from 57 election campaigns across twelve countries using a comparative framework with consistent definitions of pledge fulfillment.

Key Findings:

* Governance Boosts Pledging: Parties entering executive positions (even without legislative majorities) significantly increase their number and credibility of pre-election pledges compared to parties that do not gain such power.

* Single-Party Rule is Strongest: The highest pledge fulfillment rates occur in single-party government systems, regardless of whether the party holds an absolute majority or not.

* Coalition Dynamics Matter: In coalition governments, a party's likelihood of fulfilling its promises depends on both receiving the chief executive position and inheriting similar pledges from other governing parties.

Implications: This large-scale analysis challenges the stereotype that political parties universally break their campaign promises. It demonstrates how governing power fundamentally shapes parties' behavior regarding accountability to voters.