Developmental state theories are one of comparative socio-political economy?s most prominent modes of explaining cases of state-led successful economic development. Nonetheless, while they had greatly improved our understanding of the positive functions states can play in industrial development, and the mechanisms through which they do so, to date they have proved to be inadequate in explaining the differences between diverse successful state-led economic-development. We know a lot about how state?s structure can influence development, but we know much less about why different development states succeed or fail in different ways, industries, and periods.Recently, a new cohort of scholars, termed throughout this paper as the neo-developmental statists, has come up with an explanation for these puzzles. The neo-developmental statitsts contend that for success in high technology industries, unlike in more mature industries, there is a need for a different state structure ? the networked structure. If, so the argument goes, in the past the Japanese state managed to lead a miraculous economic growth by concentrating on an ever-more complex set of mature and maturing industries and by commanding and controlling the Japanese industry, in the global world of the high-technology industry a different structure of state-industry relationships is needed ? one that relies on meshed networks of state and industry (Ansell 2000; Evans 1995. Pp. 14-15.; O'Riain 2000; O'Riain 2004). Accordingly, if, for example, we want to understand why Japan succeeded in manufacturing cars but failed in software, while Ireland rose to prominence with its software industry, the only thing we need to understand is the extremely different structure of state-industry relations in the two countries. The neo-developmental state theorists proposed a categorization of developmental states based on their structure, arguing that different structures prove more efficient in different times and with different industries. This is an elegant, simple, and aesthetically pleasing explanation. Nevertheless, this paper argues it is wrong. By neglecting ideology, a cornerstone of the early development state theories, both the neo-developmentalists and their structuralist counterparts have missed the overarching cause behind all the differences that they have been trying to explain. Where in ideology I define the framework in which policy makers and businessperson alike construct, and even more importantly, legitimize their actions and mobilize mass support. This paper argues that if we want to understand the difference between successful developmental states, we should focus not only on their structure, but also on their economic-nationalist ideology (hereby: econonationalist ideology). It is the econonationalist ideology that defines what the proper roles of state in industry and industry in state are, what the proper shape of the national industry should be, and who should own it. Looking at structure alone, I contend, is insufficient. Only by understanding the roles of both structure and ideology can we fully understand the differences between varied cases of state-led development. In order to advance this argument, this paper subjects it to a strong test using the critical case study method (King et al. 1994; Ragin 1987; Van Evera 1997; Yin 1994). It compares the structure of the ideal-type ?old? style developmental state ? Japan ? with the ideal-type ?neo? or ?networked? developmental state ? Ireland. This comparison is done in order to first, show that in fact state-industry structure in Japan and Ireland is similar enough that we need to conclude that it adheres to the same model. Second, the comparison aims to show that the significant differences between the two cases are much better explained by econonationalist ideology, not by structure. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]