the.com/war chest

means A fund of money set aside in advance to pay for a future battle, campaign, or contest — political, corporate, or literal.

from Literal at first: a real chest or strongbox used to carry and guard a military treasury — the coin needed to pay soldiers, buy supplies, and keep an army fighting. As paper money and banking took over, the physical chest faded, but the phrase marched on into politics and business by the 20th century, where 'war chest' now means campaign funds or a corporate cash reserve kept ready for competitive fights that have nothing to do with actual war.