Tactics is how you win battles. Strategy is how you use battles to achieve national objectives.
Every battle should be for a militarily achievable objective. A better way to say it would be: "Tactics is how you achieve the militarily achievable. Strategy is how you use sub-objectives, including militarily achievable ones, to reach objectives that are not militarily achievable." But not as snappy.
"That government of the people, for the people, and by the people, shall not perish" is not something that can be accomplished by pure force of arms. Force of arms can surely contribute to it, when combined with malice toward none in the peace terms.