It was immediately challenged by realism (a millennia old, commonsense, approach) and lost the first inter-paradigm debate with the onset of WWII. Many such debates took place since then but realism and liberalism (as grandtheories) still remain the most popular approaches to IR.
The thing is, IR has expanded into (rather, is borrowing from) a vast variety of different disciplines and deals with a wide variety of issues, some of which have nothing to do with peace. Furthermore, in most cases, the IR discipline, rather than promoting the betterment of humanity, has become a legitimate means of furthering national interests and justifying state behavior. While I espouse the virtues of realism, I can't help but feel that the presence of realism in IR academia is counterproductive to promoting international peace. On the other hand, I can't help but feel that liberalism, despite all of its inherent soundness, is destined fail because of its fundamentally naive (in my personal opinion) inception of human nature and, therefore, it will never be able to completely end war.
So, I ask you: Should IR be purged of realism so as to return the discipline back to its roots and to silence those academics who legitimize power politics? Or is the discipline