America's lack of effective long-range escort for strategic bombardment was the Army Air Force's worst failure of World War II. The basic cause for peacetime negligence of long-range escort development was that air power decisions were influenced more by budget considerations and less by sound doctrine. This historical study uses a chronological approach to describe the evolution of long-range fighter escort. Air power doctrine was driven by technical advances and consisted of untried theories. The advent of the all metal mono-plane gave credibility to the emerging doctrine of strategic bombardment. The Air Corps became polarized between bomber and pursuit advocates, where the dominate doctrine of employing self-protecting bomber formations devalued the role of long-range escort. Money was viewed as the critical ingredient for building air power while doctrine was secondary. The desire to attain air power during an era of constrained budgets produced unhealthy competition between the Army and Navy. Restrictive budgets also required prioritization of research and development and production programs. Several efforts failed to produce multi-purpose aircraft that would also fulfill the escort role. The Spanish Civil War experience proved the need for long-range escort. This late realization prompted the programs that eventually produced an effective long-range escort.