Why might a political party rely on a well-known leader's past popularity?

A political party may rely on a well-known leader's past popularity primarily to attract undecided voters. A leader with a strong and positive public image can generate significant interest and support for the party, especially among those who are unsure of their voting preferences. Their established reputation can inspire trust and confidence in voters who might associate the party with the leader's previous successes or appeal. This can be particularly effective during elections when attracting swing voters is crucial for gaining a competitive advantage.

In contrast, the other options focus on different strategies that might not directly relate to leveraging a leader's popularity. Innovating party policies could be beneficial for attracting a new base of voters, but it doesn’t necessarily rely on past popularity. Diminishing rival party influence generally involves differentiating policies or strategies rather than relying on a leader’s reputation. Reducing campaign costs is a practical concern but is not directly connected to a leader's appeal; it relates more to organizational strategies rather than voter attraction.