Robot Nemesis by E.E. Smith

The War of the Planets is considered to have ended on 18 Sol, 3012, with that epic struggle, the Battle of Sector Ten. In that engagement, as is of course well known, the Grand Fleet of the Inner Planets -- the combined space-power of Mercury, Venus, Earth, and Mars -- met that of the Outer Planets in what was on both sides a desperate bid for the supremacy of interplanetary space.

But, as is also well known, there ensued not supremacy, but stalemate. Both fleets were so horribly shattered that the survivors despaired of continuing hostilities. Instead, the few and crippled remaining vessels of each force limped into some sort of formation and returned to their various planetary bases.