Once the Dominion achieved a foothold in the Alpha Quadrant via Gul Dukat's betrayal of the Cardassians, 
many analysts claimed that war was inevitable. Starfleet had been gearing up for war for almost three years, but when the Dominion began bringing both warships and supply vessels through the wormhole several hundred at a time, it became clear that the Federation would soon face a foe that was all but impossible to defeat. 
The mysterious disappearance of several Starships along the Dominion border made their intentions clear, but the most telling moment came when the Dominion began to secure non-aggression treaties with various Alpha Quadrant powers - most notably including the Romulans. Facing an opponent which grew stronger by the week whilst its own support faded, the Federation was left with little choice but to act. Some military strategists suggested an all-out surprise attack on the Dominion, but Federation ethics forbade such a course of action. Instead, it was decided to close the wormhole to further Dominion reinforcements. 
It was hoped that this would provoke the Dominion into an attack on Deep Space Nine; Starfleet knew that the capabilities of the new weapons array on the station would be common knowledge after the Klingon attack, and hoped that this would make the Dominion commit a large force from the nearest fleet base. Capturing the station would cost the Dominion heavily, giving them a purely phyrric victory since the minefield operated independently of the station and would be virtually impossible to clear anyway.
Whilst the Dominion was occupied at the station, Starfleet planned to send a Federation-Klingon task force across the border into Dominion space to attack and destroy the shipyards at Taurus III, putting a significant dent in warship production.  This fleet would then head back to the station and recapture it from the weakened fleet after only a few days under Dominion control. The overall outcome of the operation would be to inflict a heavy loss on the Dominion fleet and support system.
The first phase of the plan went exactly as expected - the minefield was completed and activated in time and the Dominion lost over fifty ships in the battle to capture Deep Space Nine, while the allies scored a notable victory at the shipyards.  Unfortunately, the fleet which set out to recapture the station was defeated and forced into retreat with heavy losses, a pattern which repeated itself many times over the next few months.
Nevertheless, the operation was considered a success by Starfleet. The wormhole remained closed, and although the station remained in Dominion hands it was able to contribute little to the war due to the sabotage undertaken by the crew when they abandoned it. Ultimately the stations recapture would become a priority which would lead to the "Valley of Death" battle, the first major allied victory in the war.