When President Woodrow Wilson ordered approximately 150,000 National Guardsmen to the southern border in 1916, the United States was on the verge of all-out war with Mexico. The rapid mobilization and deployment of the Guard forces broke the rapid escalation of violence, averted immediate war, changed the environment, and were instrumental in shifting the initiative, tactically and diplomatically, back to the Americans. Although there was no decisive victory by General John J. Pershing's punitive expedition deep inside Mexico and the National Guard struggled to meet the War Department's division-level collective readiness expectations, their ability and commitment to mobilizing quickly resulted in termination of the conflict on terms favorable to the United States. While reviewing literature on this topic, two common themes emerged. The first was that few writers have written, in any depth, regarding the operational and strategic impact of the National Guard's 150,000 soldier deployment to the border. The second is that few writers attribute the termination of hostilities to that deployment. This paper reviews President Wilson's actions and misunderstanding of the problem. It also briefly describes how the National Guard (organized militia) evolved very quickly. And finally it attempts to cast a different light on the Pershing Punitive Expedition to illustrate how this action inadvertently incriminated the environment and escalated tensions to near all-out war. Amidst war plans which lacked substance for mass mobilization, an extremely short time-line, toxic rhetoric from preparedness-movement advocates, and confusion about their new role under the Defense Act of 1916, the citizen soldiers got to the border quickly and changed the dynamics of the environment. It was not a decisive victory but Wilson understood it was good enough.