Star Trek: 10 Starfleet Decisions With The Most Devastating Consequences
9. The Battle Of Wolf-359
When the Borg finally arrived in Federation space, Admiral Hansen quickly set about mobilizing the fleet against the Cube. While the Borg sent only one vessel to assimilate Starfleet, it proved to be a deadly foe. It was given yet more strength with the addition of Captain Jean-Luc Picard, wherein lay a devastating tactical error on Starfleet's part.
Picard was assimilated into the Collective, becoming Locutus of Borg. This led to the Hive gaining all of the experience and knowledge of the captain - including Starfleet's strength, fleet deployments, and battle plans. While Acting-Captain Riker played on this to his strength, Admiral Hansen was not so lucky.
The fleet that gathered at Wolf 359, already known to Picard, was decimated by the Cube. 39 vessels were lost, with an estimated 11,000 lives ended that day. Only one ship - the USS Ahwannee - managed to escape the slaughter. Though clearly, Picard wasn't at fault, Admiral Hansen failed to take the addition of the man's expertise to the Collective's knowledge into account. This, though a tragic error, led to the deaths of all of those servicemen.
Having said that, changing the plan may simply have delayed the inevitable. The Borg, after a year of waiting, were coming.