“In war, then, let your great object be victory, not lengthy campaigns.”
The objective should govern the campaign; activity that continues without advancing the actual goal wastes resources and creates new vulnerabilities.
Source details
The Art of War, Chapter II “Waging War,” section 19, Lionel Giles translation (1910), printed page 16 / scan leaf 72 in Giles’s original full edition on Wikisource, cross-checked against Project Gutenberg #17405. “In war, then, let your great object be victory, not lengthy campaigns” is the chapter’s concluding strategic principle immediately before the statement about the commander and the people’s fate. It remains ancient battlefield/statecraft argument, not current military operational advice or a context-free productivity maxim.