We provide a theoretical exegesis and empirical assessment of the competitive factors that give communities an edge in expanding employment opportunities and protecting themselves against recessions. Four multiple-variable explanatory constructs are derived from human ecological theory and from neo-Marxian, neo-Weberian, and “new class” theories found in paradigms comprising “the new urban sociology.” Next, we apply shift-share techniques to employment change data for 3,101 American counties during recent national recession and recovery periods to decompose these changes into those accounted for by (1) national economic conditions, (2) county industrial mix, and (3) competitive effects specific to each county. The third component (competitive effects) then serves as the dependent variable for block model analysis that assesses the relative importance of the four theoretical constructs in creating local competitive dynamics. Ecological factors are the dominant predictors of local competitive effects throughout all phases of the business cycle.