The objective of this article is to develop a novel distinction among four IR approaches and especially to highlight the approach which will be called here 'offensive liberalism'. This four fold division is based not only on a distinction between realism and liberalism, but also on an internal division inside each camp between offensive and defensive approaches. Indeed, besides the distinction between offensive and defensive realism, there is also an overlooked parallel distinction between offensive and defensive liberalism. As I will show, this distinction goes deeper and has lasted much longer than the recent debate on the neoconservative agenda during the Bush presidency. While sharing the same liberal objectives, offensive and defensive liberals diverge sharply in the means they are willing to deploy to advance these objectives, especially the use of force to democratise non-democratic societies. I evaluate the advantages and the shortcomings of each approach as an avenue to fulfilling a durable world or regional peace and security. Each approach has some appeal but also major disadvantages. I will examine what the different perspectives suggest on the road to accomplishing security and peace. I will also briefly contrast the liberal and realist approaches with some constructivist ideas on peace. Finally, in order to clarify the differences among the four approaches, I apply their logic to a concrete issue, which led to major debates recently: democracy promotion and regime change by the leading superpower - the US. Thus, I open the discussion in this article by presenting the variations of ideal-type strategies towards regime change and conclude the article by linking these strategies and relevant examples to the approaches.