I was slightly off. The phrase, I later learned, is not Bloom's own but Cary Nelson's. Now, after reading Nelson's enlightening review of Bloom's The Best Poems in the English Language in Virginia Quarterly Review, I see that it very well could have been Bloom's own, as Bloom used similar martial rhetoric in a famous piece in the Boston Review, which Nelson cites as follows:
In Bloom's much-attacked Boston Review piece, he turned a military metaphor from Thucydides—"They have the numbers; we, the heights"—into a cultural claim, one intended to evoke a horde of multiculturalists about to overwhelm those few white cultural stalwarts in possession of the truth. It was reprinted as the introduction to Bloom's The Best of the Best American Poetry: 1988—1997, where he castigates Adrienne Rich for her inclusion of "enemies of the aesthetic who are in the act of overwhelming us" (16) in her own anthology, The Best American Poetry 1996. Bloom has in mind, among others, such Native American poets as Sherman Alexie and Adrian Louis. Always convinced he has one hand securely grasping the eternal verities, Bloom regrettably has the other hand embedded in racist cultural temptations he might better have resisted.
Nelson argues that Bloom's 'horde' metaphors are inflected with racism, and I agree. With the line from Thucydides and the declaration of 'enemies' beseiging the tower of the aesthetic, Bloom shows that he is effectively the author of the phrase by which Nelson condemns him. Bloom is disingenuous in citing the phrase as evidence of persecution, since he has done more than enough to provoke such cutting attacks.
Nelson's review is also quite interesting to me because of its many learned references to favorite poems excluded by Bloom. I was pleased to be pointed to Hopkins' "The Windhover," which I hadn't read in years (I still like "Pied Beauty" better). I also enjoyed taking a look at Claude McKay's fighting sonnet "The Mulatto" again (included in full in Nelson's review). Nelson does us the service of supporting the aesthetic power of such poems as McKay's, which lead listeners and readers not to ponderous contemplation, but to a desire for action, for justice. (On Nelson's recommendation here I'm also now curious to read Melvin Tolson's Libretto for the Republic of Liberia (1953) as well as Aaron Kramer's Denmark Vesey.) Nelson finds a rigorous standard by which to include poems from aesthetic sensibilities other than the 'lofty' and 'sublime' that Bloom favors above all:
Part of what recent theories that Bloom hates have taught us is that the transcendental is not transcendent. It is produced in time, by people facing difficulty and aspiration. It occurs as often as not in poems confronting specific historic occasions, just as so many abstract notions—justice, decency, faith—are formulated out of need, in the face of their historical betrayal. Part of what the poems Bloom casts into the abyss regularly do is offer the most telling and concise historical testimony possible. They do so, as Bloom recognizes for the poems he admires, by radical exploitation of the figurative power of the language. In poetry an era can sometimes be compressed into a stanza. Miraculously, it will sometimes seem that none of that era's complications have been slighted. Extraordinary? Certainly, but the extraordinariness is of insight, compression, and representation—and of a complementary power of implication—not the extraordinary illusion of leaving lived time behind.
By finding a working explanation for poetry's power for encapsulation, Nelson resolves a problem experienced by those of us who aim to be at once historicists and serious critics of aesthetic value.
Thanks to Tom Genoways (editor of Virginia Quarterly Review, no less) for the link and the suggestion.