Like I said before, that whole thing with bringing the Romulans... or rather,
tricking them into joining the war
is an embodiment of the whole "The needs of the many outweigh the needs of the few or the one". Under the circumstances, I think Starfleet would have endorsed Garak's plan(even knowing all it involved). I mean remember Starfleet is also the same organization that engineered a virus to kill all the founders, basically nothing less than 100% genocide.
I mean yes you can argue section 31 is a rogue organization not endorsed by Starfleet, but when you consider Starfleet refused to hand over the vaccine to the mutagenic virus they became no better than the Dominion. Ethically it may be a challenge, but once you do the next worst thing, refusing to hand over the cure to your enemies disease... the grounds of "The needs of the many..." starts to seem kind of shaky. "But mommy, I thought the bad guys were the only ones that committed mass genocide,". Let me also stress this even further. We're not just talking about genocide, we're talking about an attempt to extinguish an entire race.