This research work discusses the various ideas on, and various roles of Christian belief that affect communities, national and international policies. To do this, initially the origins and characteristics of phenomena such as; secularism, post-secular era, de-secularization have been briefly examined with the help of various scholars' perspectives. Following these, the next step has been to share knowledge to understand the topics focused, Christian denominations such as Evangelicalism and Christian Zionism. The historical background and the development processes of these denominations have been briefly reviewed. Lastly, the third chapter have been formulated by examining the developments regarding the contemporary roles of these Christian denominations, with the perspectives, constructed by the information from the first two chapters. As a result of these evaluations; today it can be argued that the Enlightenment's restrictive effects on church and religion's influence on public sphere, seem not much that prevailing in some fields within aforementioned societies and their politics.