Because the immediacy of the referent may be lost on future generations of readers. On Eileen Joy's advice, I looked up Eduardo Cadava's "Words of Light: Theses on the Photography of History" [JSTOR]. Glad I did—the article's quite good—but the non-specificity of this sentence irks me:
[Benjamin's] insistence on the necessity of addressing these questions and relations today—then in the 1930s as well as now, under the light or darkness of a scarcely less disastrous historical moment—is above all, a call to responsibility, a call that requires a passionate and determined effort of reflection.
The footnote explains that Cadava speaks of "the tragedy of what we now refer to as the 'War in the Gulf.'" Fair enough. Mention the "War in the Gulf" and everyone will know exactly what you're talking about.
UPDATE! Just in case it ain't absolutely plain, I really really liked Cadava's essay; found it charmingly Benjaminian, which as critical modes go, I absolutely love. There was just this one moment that reminded me of annoying moments in other essays. Note how I don't slam Cadava for what he accounts for in his footnotes...because he accounts for it in his footnotes. So please, no more hate mail. (Or at the very least, reserve it for when I actually lash out at somebody unjustly.)