Clear communication is generally viewed as a requisite to the peaceful resolution of international crises. The success of bargaining, deterrent, and compellent strategies hinges on the credibility afforded by unambiguous signals exchanged between opponents. Despite the acknowledged importance of this 'communication factor,' little effort has been made to evaluate the relative effectiveness of the various modes of communication that may be employed in crisis. By means of theoretical and comparative case analysis, this study finds a substantial difference between the efficacy of traditional diplomatic negotiation and tacit measures, such as the deployment and/or exercise of military forces near the scene of crisis. Where negotiation alone often fails, backing, preceding, or, at times, replacing diplomacy with tacit measures affords the greatest chances for success. The policy implications of this finding are explored, particularly as they apply to U.S. regional 'extended deterrent' strategies for protecting geographically distant friends and interests.