We identify a commitment problem that prevents bidders from unseating resisting and entrenched incumbent directors of target companies through proxy fights. We discuss potential remedies and argue that activist investors are more resilient to this commitment problem and can mitigate the resulting inefficiencies by putting such companies into play. This result holds even if bidders and activists have similar expertise and can use similar techniques to challenge the incumbents, and it is consistent with the evidence that most proxy fights are launched by activists, not by bidders. Building on this insight, we study the implications of activist interventions on the M&A market.