This study develops a novel theory of electoral accountability. Candidates strategically decide whether to commit to constituency service or advertise their platform through costly campaigns. We find that campaign costs increase voter welfare when partisan imbalance is low, but have the opposite effect under these conditions. Under high partisan imbalance, higher campaign spending paradoxically leads to greater expected levels of constituency service commitment from candidates. This suggests that expensive electoral campaigns can actually improve representation quality in polarized political environments by encouraging more substantive service promises. The findings challenge conventional wisdom about campaign finance regulation and provide new insights into the complex relationship between campaign expenditures and democratic accountability mechanisms.
