In a competitive market, all firms are subject to attacks from rivals. Offensive
attacks can come both from new entrants and from established firms seeking
to improve their market positions. The purpose of defensive strategy is to
lower the risk of being attacked, weaken the impact of any attack that occurs,
and influence challengers to aim their efforts at other rivals. While defensive
strategy usually doesn't enhance a firm's competitive advantage, it should help
fortify a firm's competitive position and sustain whatever competitive advantage
it has.