Wartime is exactly when centralized control breaks down the hardest, because conditions start changing incredibly fast and communication breaks down. There's a reason the phrase is "fog of war" and not "fog of peace"!
In management, what it means is having to repeatedly make decisions that are in the best interest of the company, but not necessarily in the best interest of the people on your team. This could mean needing to fire people, conduct layoffs, merge teams together and remove redundancies, strip a manager of their direct reports or reduce their scope, replace a leader, drive a major re-org that changes people's jobs in ways they may not like, shut down an entire project or team that isn't succeeding even though it's very popular or well-liked in the organization, own a technical decision that hurts one or two teams but helps the overall organization enough to offset it, etc.
In management, what it means is having to repeatedly make decisions that are in the best interest of the company, but not necessarily in the best interest of the people on your team. This could mean needing to fire people, conduct layoffs, merge teams together and remove redundancies, strip a manager of their direct reports or reduce their scope, replace a leader, drive a major re-org that changes people's jobs in ways they may not like, shut down an entire project or team that isn't succeeding even though it's very popular or well-liked in the organization, own a technical decision that hurts one or two teams but helps the overall organization enough to offset it, etc.