This descriptive study focuses on analyzing the factors influencing public debate on intensified Finnish-Swedish defence cooperation, using qualitative abductive content analysis (a combination of Grounded theory analysis and text/content analysis) as the research method. The study was conducted using a model adapted from Tomas Valasek’s hypothesis on pooling and sharing (Surviving Austerity - The case for a new approach to EU military collaboration, 2011), inducted from a corpus collected from Finnish and Swedish public defence debates from 1.1.2013 to 31.3.2014. The main research question is: what are the driving forces influencing debate on intensified bilateral Finnish-Swedish defence. Secondary research questions were developed from the corpus in four categories: historical, political/military, economic and attitudinal factors. Using these as the analysis model, the corpus was deductively analyzed to increase understanding of the individual factors and to find driving forces. The main result of this study is that the existence or lack of trust is seen as a key driving force influencing debate, either furthering or hindering cooperation. Other driving forces seen as influencing debate are the existence or lack of: understanding of the historical background of cooperation from both countries’ point of view commitment and clarity of political/military goals political commitment to the political/military purposes of cooperation instead of domestic economic gain a legally binding framework for cooperation.