The battle lines are drawn. On the one hand, the First World War was a necessary struggle and Britain had no alternative but to play its part: on the other, the war was a tragic mess that came about by mistake, and we should have stayed out. Bungling statesmen got us into it, and bungling generals made sure it would be a four-year nightmare of futile slaughter.

Source:

http://www.independent.co.uk/voices/comment/should-britain-have-joined-world-war-one-keep-these-points-in-mind-during-the-argument-9322604.html