This paper empirically investigates the effect of leverage on strategic preemption. Using new data on entry plans and incumbent investments from the American casino industry, I find that high leverage prevents incumbents from responding to entry threats. Facing the same set of entry plans, low-leverage incumbents expand physical capacity (by 30%), whereas high-leverage incumbents do not. This difference in investment matters because capacity installations preempt eventual entry. Stock market reactions to withdrawn plans imply that effective preemption increases incumbent firm value by 5%. My findings suggest that leverage matters for industry composition, not just firm-level investment.