""[T]here will be no turning back,"" said Lt. Gen. Ulysses S. Grant. It was May, 1864. The Civil War had dragged into its fourth spring. It was time to end things, Grant resolved, once and for all.With the Union Army of the Potomac as his sledge, Grant crossed the Rapidan River, intending to draw the Army of Northern Virginia into one final battle. Short of that, he planned ""to hammer continuously against the armed forces of the enemy and his resources, until by mere attrition, if in no other way, there should be nothing left to him . . . .""Almost immediately, though, Robert E. Lee's Confede