From Wikipedia article on "Situational ethics"
Situational ethics, or situation ethics, takes into account the particular context of an act when evaluating it ethically, rather than judging it according to absolute moral standards. In situation ethics, within each content it is not a universal law that is to be followed, but the law of love. The Greek word used to describe love in the Bible is "agape". Agape is the type of love that shows concern about others, caring for them as much as you care for yourself. Agape love has no strings attached to it, it seeks nothing in return. you love someone completely unconditionally. Early proponents of situational approaches to ethics included Kierkegaard, Sartre, de Beauvoir, Jaspers, and Heidegger.
Specifically Christian forms of situational ethics placing love about all particular principles or rules were proposed in the first half of the twentieth century by Rudolf Bultmann, John A. T. Robinson, and Joseph Fletcher. These theologians point specifically to agapē, or unconditional love, as the highest end. Other theologians who advocated situational ethics include Josef Fuchs, Reinhold Niebuhr, Karl Barth, Emil Brunner, Dietrich Bonhoeffer, and Paul Tillich.:33 Tillich, for example, declared that "Love is the ultimate law."
Fletcher, who became prominently associated with this approach in the English-speaking world due to his eponymously titled book (Situation Ethics), stated that "all laws and rules and principles and ideals and norms, are only contingent, only valid if they happen to serve love" in the particular situation,:30 and thus may be broken or ignored if another course of action would achieve a more loving outcome. Fletcher has sometimes been identified as the founder of situation ethics, but he himself refers his readers to the active debate over the theme that preceded his own work.