In party competition, clarity in policy promises isn't always the best strategy. This paper argues ambiguous platforms can strategically attract diverse voter groups.

The research develops a formal model of multi-party competition where leaders balance demands from two principals—the general public and party core constituents. Using data from Eurobarometer surveys and electoral manifestos analyzed via Wordscores, we estimate platform ambiguity.

Our findings reveal that when the preferences of these two groups diverge significantly:

• Platforms become more intentionally vague

• Strategic positioning benefits parties across 14 Western European democracies

This suggests in certain political environments, deliberately unclear policy positions can be an effective strategy for gaining broad electoral support.