The Union faced a severe challenge in the summer of 1864 as their armies suffered high casualties but failed to break the rebellion. By August, Lincoln expected that he would lose his re-election bid to former general George McClellan, who called for a ceasefire and negotiation with the Southern states. After Farragut captured Mobile and General Sherman's Union army captured Atlanta, however, Northern sentiment shifted back in favor of Lincoln and his strategy of continuing the war until the Confederacy surrendered.
At this critical moment in American history, Farragut entered Mobile Bay on August 5th, 1864. His ironclad monitors led and a fleet of mostly wooden ships that were far more vulnerable to Confederate gunfire and mines (known at that time as torpedoes. After Farragut's lead monitor, the Tecumseh, was destroyed by a mine, the commander of the next ship in the line stopped, causing the line of ships to drift apart. Disaster seemed imminent as his flotilla appeared pinned between Confederate mines and the Confederate batteries on the shore.
At this moment, Farragut gave his famous order to move forward despite the danger. He maneuvered his own ship in front of the line and steered through the minefield. Luck as much as bravery appears to have been on Farragut's side as some of them mines may have simply failed to explode. After navigating through the mines, the Union fleet overwhelmed the Confederate vessels and overwhelmed the three Confederate forts which surrendered rather than face destruction or starvation now that they were isolated and could not be reinforced or resupplied now that Farragut controlled both Mobile Bay and the river.