Definition from Wiktionary, the free dictionary
Literally "at war as at war".
à la guerre comme à la guerre
- In time of crisis, all means are good for achieving one's goals; roughly all's fair in love and war, or the ends justify the means.
- One must make the best of one's situation, or make do with what one has; roughly keep a stiff upper lip, or when life gives you lemons, make lemonade.