- Marginal seat
A marginal seat, or swing seat, is a constituency held with a particularly small majority in a legislative election, generally conducted under a single-winner voting system. In Canada they may be known as target ridings. The opposite is a safe seat.
These seats require a smaller swing to change hands and therefore are typically the focus of most campaign resources. The concentration of money and manpower to areas where they will make the most difference is known as targeting.
Strategies for securing swing seats
Political parties often face tension between the holders of marginal seats and safe seats. Holders of safe seats tend to get far less discretionary resources—governmental as well as political—from their political party than do holders of marginal seats.
A similar phenomenon happens in United States presidential elections, where the Electoral College system means that candidates must win states rather than votes. Again, resources are concentrated towards the swing states with the smallest majorities.
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